Commit | Line | Data |
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71e3aac0 AA |
1 | /* |
2 | * Copyright (C) 2009 Red Hat, Inc. | |
3 | * | |
4 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
5 | * the COPYING file in the top-level directory. | |
6 | */ | |
7 | ||
8 | #include <linux/mm.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/highmem.h> | |
11 | #include <linux/hugetlb.h> | |
12 | #include <linux/mmu_notifier.h> | |
13 | #include <linux/rmap.h> | |
14 | #include <linux/swap.h> | |
97ae1749 | 15 | #include <linux/shrinker.h> |
ba76149f AA |
16 | #include <linux/mm_inline.h> |
17 | #include <linux/kthread.h> | |
18 | #include <linux/khugepaged.h> | |
878aee7d | 19 | #include <linux/freezer.h> |
a664b2d8 | 20 | #include <linux/mman.h> |
325adeb5 | 21 | #include <linux/pagemap.h> |
4daae3b4 | 22 | #include <linux/migrate.h> |
43b5fbbd | 23 | #include <linux/hashtable.h> |
97ae1749 | 24 | |
71e3aac0 AA |
25 | #include <asm/tlb.h> |
26 | #include <asm/pgalloc.h> | |
27 | #include "internal.h" | |
28 | ||
ba76149f AA |
29 | /* |
30 | * By default transparent hugepage support is enabled for all mappings | |
31 | * and khugepaged scans all mappings. Defrag is only invoked by | |
32 | * khugepaged hugepage allocations and by page faults inside | |
33 | * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived | |
34 | * allocations. | |
35 | */ | |
71e3aac0 | 36 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 37 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 38 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
39 | #endif |
40 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
41 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
42 | #endif | |
d39d33c3 | 43 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| |
79da5407 KS |
44 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)| |
45 | (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
ba76149f AA |
46 | |
47 | /* default scan 8*512 pte (or vmas) every 30 second */ | |
48 | static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; | |
49 | static unsigned int khugepaged_pages_collapsed; | |
50 | static unsigned int khugepaged_full_scans; | |
51 | static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; | |
52 | /* during fragmentation poll the hugepage allocator once every minute */ | |
53 | static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; | |
54 | static struct task_struct *khugepaged_thread __read_mostly; | |
55 | static DEFINE_MUTEX(khugepaged_mutex); | |
56 | static DEFINE_SPINLOCK(khugepaged_mm_lock); | |
57 | static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); | |
58 | /* | |
59 | * default collapse hugepages if there is at least one pte mapped like | |
60 | * it would have happened if the vma was large enough during page | |
61 | * fault. | |
62 | */ | |
63 | static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; | |
64 | ||
65 | static int khugepaged(void *none); | |
ba76149f | 66 | static int khugepaged_slab_init(void); |
ba76149f | 67 | |
43b5fbbd SL |
68 | #define MM_SLOTS_HASH_BITS 10 |
69 | static __read_mostly DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); | |
70 | ||
ba76149f AA |
71 | static struct kmem_cache *mm_slot_cache __read_mostly; |
72 | ||
73 | /** | |
74 | * struct mm_slot - hash lookup from mm to mm_slot | |
75 | * @hash: hash collision list | |
76 | * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head | |
77 | * @mm: the mm that this information is valid for | |
78 | */ | |
79 | struct mm_slot { | |
80 | struct hlist_node hash; | |
81 | struct list_head mm_node; | |
82 | struct mm_struct *mm; | |
83 | }; | |
84 | ||
85 | /** | |
86 | * struct khugepaged_scan - cursor for scanning | |
87 | * @mm_head: the head of the mm list to scan | |
88 | * @mm_slot: the current mm_slot we are scanning | |
89 | * @address: the next address inside that to be scanned | |
90 | * | |
91 | * There is only the one khugepaged_scan instance of this cursor structure. | |
92 | */ | |
93 | struct khugepaged_scan { | |
94 | struct list_head mm_head; | |
95 | struct mm_slot *mm_slot; | |
96 | unsigned long address; | |
2f1da642 HS |
97 | }; |
98 | static struct khugepaged_scan khugepaged_scan = { | |
ba76149f AA |
99 | .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), |
100 | }; | |
101 | ||
f000565a AA |
102 | |
103 | static int set_recommended_min_free_kbytes(void) | |
104 | { | |
105 | struct zone *zone; | |
106 | int nr_zones = 0; | |
107 | unsigned long recommended_min; | |
f000565a | 108 | |
17c230af | 109 | if (!khugepaged_enabled()) |
f000565a AA |
110 | return 0; |
111 | ||
112 | for_each_populated_zone(zone) | |
113 | nr_zones++; | |
114 | ||
115 | /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ | |
116 | recommended_min = pageblock_nr_pages * nr_zones * 2; | |
117 | ||
118 | /* | |
119 | * Make sure that on average at least two pageblocks are almost free | |
120 | * of another type, one for a migratetype to fall back to and a | |
121 | * second to avoid subsequent fallbacks of other types There are 3 | |
122 | * MIGRATE_TYPES we care about. | |
123 | */ | |
124 | recommended_min += pageblock_nr_pages * nr_zones * | |
125 | MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; | |
126 | ||
127 | /* don't ever allow to reserve more than 5% of the lowmem */ | |
128 | recommended_min = min(recommended_min, | |
129 | (unsigned long) nr_free_buffer_pages() / 20); | |
130 | recommended_min <<= (PAGE_SHIFT-10); | |
131 | ||
132 | if (recommended_min > min_free_kbytes) | |
133 | min_free_kbytes = recommended_min; | |
134 | setup_per_zone_wmarks(); | |
135 | return 0; | |
136 | } | |
137 | late_initcall(set_recommended_min_free_kbytes); | |
138 | ||
ba76149f AA |
139 | static int start_khugepaged(void) |
140 | { | |
141 | int err = 0; | |
142 | if (khugepaged_enabled()) { | |
ba76149f AA |
143 | if (!khugepaged_thread) |
144 | khugepaged_thread = kthread_run(khugepaged, NULL, | |
145 | "khugepaged"); | |
146 | if (unlikely(IS_ERR(khugepaged_thread))) { | |
147 | printk(KERN_ERR | |
148 | "khugepaged: kthread_run(khugepaged) failed\n"); | |
149 | err = PTR_ERR(khugepaged_thread); | |
150 | khugepaged_thread = NULL; | |
151 | } | |
911891af XG |
152 | |
153 | if (!list_empty(&khugepaged_scan.mm_head)) | |
ba76149f | 154 | wake_up_interruptible(&khugepaged_wait); |
f000565a AA |
155 | |
156 | set_recommended_min_free_kbytes(); | |
911891af | 157 | } else if (khugepaged_thread) { |
911891af XG |
158 | kthread_stop(khugepaged_thread); |
159 | khugepaged_thread = NULL; | |
160 | } | |
637e3a27 | 161 | |
ba76149f AA |
162 | return err; |
163 | } | |
71e3aac0 | 164 | |
97ae1749 | 165 | static atomic_t huge_zero_refcount; |
5918d10a | 166 | static struct page *huge_zero_page __read_mostly; |
97ae1749 | 167 | |
5918d10a | 168 | static inline bool is_huge_zero_page(struct page *page) |
4a6c1297 | 169 | { |
5918d10a | 170 | return ACCESS_ONCE(huge_zero_page) == page; |
97ae1749 | 171 | } |
4a6c1297 | 172 | |
97ae1749 KS |
173 | static inline bool is_huge_zero_pmd(pmd_t pmd) |
174 | { | |
5918d10a | 175 | return is_huge_zero_page(pmd_page(pmd)); |
97ae1749 KS |
176 | } |
177 | ||
5918d10a | 178 | static struct page *get_huge_zero_page(void) |
97ae1749 KS |
179 | { |
180 | struct page *zero_page; | |
181 | retry: | |
182 | if (likely(atomic_inc_not_zero(&huge_zero_refcount))) | |
5918d10a | 183 | return ACCESS_ONCE(huge_zero_page); |
97ae1749 KS |
184 | |
185 | zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
4a6c1297 | 186 | HPAGE_PMD_ORDER); |
d8a8e1f0 KS |
187 | if (!zero_page) { |
188 | count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); | |
5918d10a | 189 | return NULL; |
d8a8e1f0 KS |
190 | } |
191 | count_vm_event(THP_ZERO_PAGE_ALLOC); | |
97ae1749 | 192 | preempt_disable(); |
5918d10a | 193 | if (cmpxchg(&huge_zero_page, NULL, zero_page)) { |
97ae1749 KS |
194 | preempt_enable(); |
195 | __free_page(zero_page); | |
196 | goto retry; | |
197 | } | |
198 | ||
199 | /* We take additional reference here. It will be put back by shrinker */ | |
200 | atomic_set(&huge_zero_refcount, 2); | |
201 | preempt_enable(); | |
5918d10a | 202 | return ACCESS_ONCE(huge_zero_page); |
4a6c1297 KS |
203 | } |
204 | ||
97ae1749 | 205 | static void put_huge_zero_page(void) |
4a6c1297 | 206 | { |
97ae1749 KS |
207 | /* |
208 | * Counter should never go to zero here. Only shrinker can put | |
209 | * last reference. | |
210 | */ | |
211 | BUG_ON(atomic_dec_and_test(&huge_zero_refcount)); | |
4a6c1297 KS |
212 | } |
213 | ||
48896466 GC |
214 | static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink, |
215 | struct shrink_control *sc) | |
4a6c1297 | 216 | { |
48896466 GC |
217 | /* we can free zero page only if last reference remains */ |
218 | return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0; | |
219 | } | |
97ae1749 | 220 | |
48896466 GC |
221 | static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink, |
222 | struct shrink_control *sc) | |
223 | { | |
97ae1749 | 224 | if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { |
5918d10a KS |
225 | struct page *zero_page = xchg(&huge_zero_page, NULL); |
226 | BUG_ON(zero_page == NULL); | |
227 | __free_page(zero_page); | |
48896466 | 228 | return HPAGE_PMD_NR; |
97ae1749 KS |
229 | } |
230 | ||
231 | return 0; | |
4a6c1297 KS |
232 | } |
233 | ||
97ae1749 | 234 | static struct shrinker huge_zero_page_shrinker = { |
48896466 GC |
235 | .count_objects = shrink_huge_zero_page_count, |
236 | .scan_objects = shrink_huge_zero_page_scan, | |
97ae1749 KS |
237 | .seeks = DEFAULT_SEEKS, |
238 | }; | |
239 | ||
71e3aac0 | 240 | #ifdef CONFIG_SYSFS |
ba76149f | 241 | |
71e3aac0 AA |
242 | static ssize_t double_flag_show(struct kobject *kobj, |
243 | struct kobj_attribute *attr, char *buf, | |
244 | enum transparent_hugepage_flag enabled, | |
245 | enum transparent_hugepage_flag req_madv) | |
246 | { | |
247 | if (test_bit(enabled, &transparent_hugepage_flags)) { | |
248 | VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); | |
249 | return sprintf(buf, "[always] madvise never\n"); | |
250 | } else if (test_bit(req_madv, &transparent_hugepage_flags)) | |
251 | return sprintf(buf, "always [madvise] never\n"); | |
252 | else | |
253 | return sprintf(buf, "always madvise [never]\n"); | |
254 | } | |
255 | static ssize_t double_flag_store(struct kobject *kobj, | |
256 | struct kobj_attribute *attr, | |
257 | const char *buf, size_t count, | |
258 | enum transparent_hugepage_flag enabled, | |
259 | enum transparent_hugepage_flag req_madv) | |
260 | { | |
261 | if (!memcmp("always", buf, | |
262 | min(sizeof("always")-1, count))) { | |
263 | set_bit(enabled, &transparent_hugepage_flags); | |
264 | clear_bit(req_madv, &transparent_hugepage_flags); | |
265 | } else if (!memcmp("madvise", buf, | |
266 | min(sizeof("madvise")-1, count))) { | |
267 | clear_bit(enabled, &transparent_hugepage_flags); | |
268 | set_bit(req_madv, &transparent_hugepage_flags); | |
269 | } else if (!memcmp("never", buf, | |
270 | min(sizeof("never")-1, count))) { | |
271 | clear_bit(enabled, &transparent_hugepage_flags); | |
272 | clear_bit(req_madv, &transparent_hugepage_flags); | |
273 | } else | |
274 | return -EINVAL; | |
275 | ||
276 | return count; | |
277 | } | |
278 | ||
279 | static ssize_t enabled_show(struct kobject *kobj, | |
280 | struct kobj_attribute *attr, char *buf) | |
281 | { | |
282 | return double_flag_show(kobj, attr, buf, | |
283 | TRANSPARENT_HUGEPAGE_FLAG, | |
284 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
285 | } | |
286 | static ssize_t enabled_store(struct kobject *kobj, | |
287 | struct kobj_attribute *attr, | |
288 | const char *buf, size_t count) | |
289 | { | |
ba76149f AA |
290 | ssize_t ret; |
291 | ||
292 | ret = double_flag_store(kobj, attr, buf, count, | |
293 | TRANSPARENT_HUGEPAGE_FLAG, | |
294 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
295 | ||
296 | if (ret > 0) { | |
911891af XG |
297 | int err; |
298 | ||
299 | mutex_lock(&khugepaged_mutex); | |
300 | err = start_khugepaged(); | |
301 | mutex_unlock(&khugepaged_mutex); | |
302 | ||
ba76149f AA |
303 | if (err) |
304 | ret = err; | |
305 | } | |
306 | ||
307 | return ret; | |
71e3aac0 AA |
308 | } |
309 | static struct kobj_attribute enabled_attr = | |
310 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
311 | ||
312 | static ssize_t single_flag_show(struct kobject *kobj, | |
313 | struct kobj_attribute *attr, char *buf, | |
314 | enum transparent_hugepage_flag flag) | |
315 | { | |
e27e6151 BH |
316 | return sprintf(buf, "%d\n", |
317 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 318 | } |
e27e6151 | 319 | |
71e3aac0 AA |
320 | static ssize_t single_flag_store(struct kobject *kobj, |
321 | struct kobj_attribute *attr, | |
322 | const char *buf, size_t count, | |
323 | enum transparent_hugepage_flag flag) | |
324 | { | |
e27e6151 BH |
325 | unsigned long value; |
326 | int ret; | |
327 | ||
328 | ret = kstrtoul(buf, 10, &value); | |
329 | if (ret < 0) | |
330 | return ret; | |
331 | if (value > 1) | |
332 | return -EINVAL; | |
333 | ||
334 | if (value) | |
71e3aac0 | 335 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 336 | else |
71e3aac0 | 337 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
338 | |
339 | return count; | |
340 | } | |
341 | ||
342 | /* | |
343 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
344 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
345 | * memory just to allocate one more hugepage. | |
346 | */ | |
347 | static ssize_t defrag_show(struct kobject *kobj, | |
348 | struct kobj_attribute *attr, char *buf) | |
349 | { | |
350 | return double_flag_show(kobj, attr, buf, | |
351 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
352 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
353 | } | |
354 | static ssize_t defrag_store(struct kobject *kobj, | |
355 | struct kobj_attribute *attr, | |
356 | const char *buf, size_t count) | |
357 | { | |
358 | return double_flag_store(kobj, attr, buf, count, | |
359 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
360 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
361 | } | |
362 | static struct kobj_attribute defrag_attr = | |
363 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
364 | ||
79da5407 KS |
365 | static ssize_t use_zero_page_show(struct kobject *kobj, |
366 | struct kobj_attribute *attr, char *buf) | |
367 | { | |
368 | return single_flag_show(kobj, attr, buf, | |
369 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
370 | } | |
371 | static ssize_t use_zero_page_store(struct kobject *kobj, | |
372 | struct kobj_attribute *attr, const char *buf, size_t count) | |
373 | { | |
374 | return single_flag_store(kobj, attr, buf, count, | |
375 | TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG); | |
376 | } | |
377 | static struct kobj_attribute use_zero_page_attr = | |
378 | __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store); | |
71e3aac0 AA |
379 | #ifdef CONFIG_DEBUG_VM |
380 | static ssize_t debug_cow_show(struct kobject *kobj, | |
381 | struct kobj_attribute *attr, char *buf) | |
382 | { | |
383 | return single_flag_show(kobj, attr, buf, | |
384 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
385 | } | |
386 | static ssize_t debug_cow_store(struct kobject *kobj, | |
387 | struct kobj_attribute *attr, | |
388 | const char *buf, size_t count) | |
389 | { | |
390 | return single_flag_store(kobj, attr, buf, count, | |
391 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
392 | } | |
393 | static struct kobj_attribute debug_cow_attr = | |
394 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
395 | #endif /* CONFIG_DEBUG_VM */ | |
396 | ||
397 | static struct attribute *hugepage_attr[] = { | |
398 | &enabled_attr.attr, | |
399 | &defrag_attr.attr, | |
79da5407 | 400 | &use_zero_page_attr.attr, |
71e3aac0 AA |
401 | #ifdef CONFIG_DEBUG_VM |
402 | &debug_cow_attr.attr, | |
403 | #endif | |
404 | NULL, | |
405 | }; | |
406 | ||
407 | static struct attribute_group hugepage_attr_group = { | |
408 | .attrs = hugepage_attr, | |
ba76149f AA |
409 | }; |
410 | ||
411 | static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, | |
412 | struct kobj_attribute *attr, | |
413 | char *buf) | |
414 | { | |
415 | return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); | |
416 | } | |
417 | ||
418 | static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, | |
419 | struct kobj_attribute *attr, | |
420 | const char *buf, size_t count) | |
421 | { | |
422 | unsigned long msecs; | |
423 | int err; | |
424 | ||
3dbb95f7 | 425 | err = kstrtoul(buf, 10, &msecs); |
ba76149f AA |
426 | if (err || msecs > UINT_MAX) |
427 | return -EINVAL; | |
428 | ||
429 | khugepaged_scan_sleep_millisecs = msecs; | |
430 | wake_up_interruptible(&khugepaged_wait); | |
431 | ||
432 | return count; | |
433 | } | |
434 | static struct kobj_attribute scan_sleep_millisecs_attr = | |
435 | __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, | |
436 | scan_sleep_millisecs_store); | |
437 | ||
438 | static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, | |
439 | struct kobj_attribute *attr, | |
440 | char *buf) | |
441 | { | |
442 | return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); | |
443 | } | |
444 | ||
445 | static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, | |
446 | struct kobj_attribute *attr, | |
447 | const char *buf, size_t count) | |
448 | { | |
449 | unsigned long msecs; | |
450 | int err; | |
451 | ||
3dbb95f7 | 452 | err = kstrtoul(buf, 10, &msecs); |
ba76149f AA |
453 | if (err || msecs > UINT_MAX) |
454 | return -EINVAL; | |
455 | ||
456 | khugepaged_alloc_sleep_millisecs = msecs; | |
457 | wake_up_interruptible(&khugepaged_wait); | |
458 | ||
459 | return count; | |
460 | } | |
461 | static struct kobj_attribute alloc_sleep_millisecs_attr = | |
462 | __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, | |
463 | alloc_sleep_millisecs_store); | |
464 | ||
465 | static ssize_t pages_to_scan_show(struct kobject *kobj, | |
466 | struct kobj_attribute *attr, | |
467 | char *buf) | |
468 | { | |
469 | return sprintf(buf, "%u\n", khugepaged_pages_to_scan); | |
470 | } | |
471 | static ssize_t pages_to_scan_store(struct kobject *kobj, | |
472 | struct kobj_attribute *attr, | |
473 | const char *buf, size_t count) | |
474 | { | |
475 | int err; | |
476 | unsigned long pages; | |
477 | ||
3dbb95f7 | 478 | err = kstrtoul(buf, 10, &pages); |
ba76149f AA |
479 | if (err || !pages || pages > UINT_MAX) |
480 | return -EINVAL; | |
481 | ||
482 | khugepaged_pages_to_scan = pages; | |
483 | ||
484 | return count; | |
485 | } | |
486 | static struct kobj_attribute pages_to_scan_attr = | |
487 | __ATTR(pages_to_scan, 0644, pages_to_scan_show, | |
488 | pages_to_scan_store); | |
489 | ||
490 | static ssize_t pages_collapsed_show(struct kobject *kobj, | |
491 | struct kobj_attribute *attr, | |
492 | char *buf) | |
493 | { | |
494 | return sprintf(buf, "%u\n", khugepaged_pages_collapsed); | |
495 | } | |
496 | static struct kobj_attribute pages_collapsed_attr = | |
497 | __ATTR_RO(pages_collapsed); | |
498 | ||
499 | static ssize_t full_scans_show(struct kobject *kobj, | |
500 | struct kobj_attribute *attr, | |
501 | char *buf) | |
502 | { | |
503 | return sprintf(buf, "%u\n", khugepaged_full_scans); | |
504 | } | |
505 | static struct kobj_attribute full_scans_attr = | |
506 | __ATTR_RO(full_scans); | |
507 | ||
508 | static ssize_t khugepaged_defrag_show(struct kobject *kobj, | |
509 | struct kobj_attribute *attr, char *buf) | |
510 | { | |
511 | return single_flag_show(kobj, attr, buf, | |
512 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
513 | } | |
514 | static ssize_t khugepaged_defrag_store(struct kobject *kobj, | |
515 | struct kobj_attribute *attr, | |
516 | const char *buf, size_t count) | |
517 | { | |
518 | return single_flag_store(kobj, attr, buf, count, | |
519 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
520 | } | |
521 | static struct kobj_attribute khugepaged_defrag_attr = | |
522 | __ATTR(defrag, 0644, khugepaged_defrag_show, | |
523 | khugepaged_defrag_store); | |
524 | ||
525 | /* | |
526 | * max_ptes_none controls if khugepaged should collapse hugepages over | |
527 | * any unmapped ptes in turn potentially increasing the memory | |
528 | * footprint of the vmas. When max_ptes_none is 0 khugepaged will not | |
529 | * reduce the available free memory in the system as it | |
530 | * runs. Increasing max_ptes_none will instead potentially reduce the | |
531 | * free memory in the system during the khugepaged scan. | |
532 | */ | |
533 | static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, | |
534 | struct kobj_attribute *attr, | |
535 | char *buf) | |
536 | { | |
537 | return sprintf(buf, "%u\n", khugepaged_max_ptes_none); | |
538 | } | |
539 | static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, | |
540 | struct kobj_attribute *attr, | |
541 | const char *buf, size_t count) | |
542 | { | |
543 | int err; | |
544 | unsigned long max_ptes_none; | |
545 | ||
3dbb95f7 | 546 | err = kstrtoul(buf, 10, &max_ptes_none); |
ba76149f AA |
547 | if (err || max_ptes_none > HPAGE_PMD_NR-1) |
548 | return -EINVAL; | |
549 | ||
550 | khugepaged_max_ptes_none = max_ptes_none; | |
551 | ||
552 | return count; | |
553 | } | |
554 | static struct kobj_attribute khugepaged_max_ptes_none_attr = | |
555 | __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, | |
556 | khugepaged_max_ptes_none_store); | |
557 | ||
558 | static struct attribute *khugepaged_attr[] = { | |
559 | &khugepaged_defrag_attr.attr, | |
560 | &khugepaged_max_ptes_none_attr.attr, | |
561 | &pages_to_scan_attr.attr, | |
562 | &pages_collapsed_attr.attr, | |
563 | &full_scans_attr.attr, | |
564 | &scan_sleep_millisecs_attr.attr, | |
565 | &alloc_sleep_millisecs_attr.attr, | |
566 | NULL, | |
567 | }; | |
568 | ||
569 | static struct attribute_group khugepaged_attr_group = { | |
570 | .attrs = khugepaged_attr, | |
571 | .name = "khugepaged", | |
71e3aac0 | 572 | }; |
71e3aac0 | 573 | |
569e5590 | 574 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 575 | { |
71e3aac0 AA |
576 | int err; |
577 | ||
569e5590 SL |
578 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
579 | if (unlikely(!*hugepage_kobj)) { | |
2c79737a | 580 | printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n"); |
569e5590 | 581 | return -ENOMEM; |
ba76149f AA |
582 | } |
583 | ||
569e5590 | 584 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f | 585 | if (err) { |
2c79737a | 586 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 587 | goto delete_obj; |
ba76149f AA |
588 | } |
589 | ||
569e5590 | 590 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f | 591 | if (err) { |
2c79737a | 592 | printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n"); |
569e5590 | 593 | goto remove_hp_group; |
ba76149f | 594 | } |
569e5590 SL |
595 | |
596 | return 0; | |
597 | ||
598 | remove_hp_group: | |
599 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
600 | delete_obj: | |
601 | kobject_put(*hugepage_kobj); | |
602 | return err; | |
603 | } | |
604 | ||
605 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
606 | { | |
607 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
608 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
609 | kobject_put(hugepage_kobj); | |
610 | } | |
611 | #else | |
612 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
613 | { | |
614 | return 0; | |
615 | } | |
616 | ||
617 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
618 | { | |
619 | } | |
620 | #endif /* CONFIG_SYSFS */ | |
621 | ||
622 | static int __init hugepage_init(void) | |
623 | { | |
624 | int err; | |
625 | struct kobject *hugepage_kobj; | |
626 | ||
627 | if (!has_transparent_hugepage()) { | |
628 | transparent_hugepage_flags = 0; | |
629 | return -EINVAL; | |
630 | } | |
631 | ||
632 | err = hugepage_init_sysfs(&hugepage_kobj); | |
633 | if (err) | |
634 | return err; | |
ba76149f AA |
635 | |
636 | err = khugepaged_slab_init(); | |
637 | if (err) | |
638 | goto out; | |
639 | ||
97ae1749 KS |
640 | register_shrinker(&huge_zero_page_shrinker); |
641 | ||
97562cd2 RR |
642 | /* |
643 | * By default disable transparent hugepages on smaller systems, | |
644 | * where the extra memory used could hurt more than TLB overhead | |
645 | * is likely to save. The admin can still enable it through /sys. | |
646 | */ | |
647 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
648 | transparent_hugepage_flags = 0; | |
649 | ||
ba76149f AA |
650 | start_khugepaged(); |
651 | ||
569e5590 | 652 | return 0; |
ba76149f | 653 | out: |
569e5590 | 654 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 655 | return err; |
71e3aac0 AA |
656 | } |
657 | module_init(hugepage_init) | |
658 | ||
659 | static int __init setup_transparent_hugepage(char *str) | |
660 | { | |
661 | int ret = 0; | |
662 | if (!str) | |
663 | goto out; | |
664 | if (!strcmp(str, "always")) { | |
665 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
666 | &transparent_hugepage_flags); | |
667 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
668 | &transparent_hugepage_flags); | |
669 | ret = 1; | |
670 | } else if (!strcmp(str, "madvise")) { | |
671 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
672 | &transparent_hugepage_flags); | |
673 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
674 | &transparent_hugepage_flags); | |
675 | ret = 1; | |
676 | } else if (!strcmp(str, "never")) { | |
677 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
678 | &transparent_hugepage_flags); | |
679 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
680 | &transparent_hugepage_flags); | |
681 | ret = 1; | |
682 | } | |
683 | out: | |
684 | if (!ret) | |
685 | printk(KERN_WARNING | |
686 | "transparent_hugepage= cannot parse, ignored\n"); | |
687 | return ret; | |
688 | } | |
689 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
690 | ||
b32967ff | 691 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
692 | { |
693 | if (likely(vma->vm_flags & VM_WRITE)) | |
694 | pmd = pmd_mkwrite(pmd); | |
695 | return pmd; | |
696 | } | |
697 | ||
3122359a | 698 | static inline pmd_t mk_huge_pmd(struct page *page, pgprot_t prot) |
b3092b3b BL |
699 | { |
700 | pmd_t entry; | |
3122359a | 701 | entry = mk_pmd(page, prot); |
b3092b3b BL |
702 | entry = pmd_mkhuge(entry); |
703 | return entry; | |
704 | } | |
705 | ||
71e3aac0 AA |
706 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, |
707 | struct vm_area_struct *vma, | |
708 | unsigned long haddr, pmd_t *pmd, | |
709 | struct page *page) | |
710 | { | |
71e3aac0 AA |
711 | pgtable_t pgtable; |
712 | ||
713 | VM_BUG_ON(!PageCompound(page)); | |
714 | pgtable = pte_alloc_one(mm, haddr); | |
edad9d2c | 715 | if (unlikely(!pgtable)) |
71e3aac0 | 716 | return VM_FAULT_OOM; |
71e3aac0 AA |
717 | |
718 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
52f37629 MK |
719 | /* |
720 | * The memory barrier inside __SetPageUptodate makes sure that | |
721 | * clear_huge_page writes become visible before the set_pmd_at() | |
722 | * write. | |
723 | */ | |
71e3aac0 AA |
724 | __SetPageUptodate(page); |
725 | ||
726 | spin_lock(&mm->page_table_lock); | |
727 | if (unlikely(!pmd_none(*pmd))) { | |
728 | spin_unlock(&mm->page_table_lock); | |
b9bbfbe3 | 729 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
730 | put_page(page); |
731 | pte_free(mm, pgtable); | |
732 | } else { | |
733 | pmd_t entry; | |
3122359a KS |
734 | entry = mk_huge_pmd(page, vma->vm_page_prot); |
735 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
71e3aac0 | 736 | page_add_new_anon_rmap(page, vma, haddr); |
6b0b50b0 | 737 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
71e3aac0 | 738 | set_pmd_at(mm, haddr, pmd, entry); |
71e3aac0 | 739 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
1c641e84 | 740 | mm->nr_ptes++; |
71e3aac0 AA |
741 | spin_unlock(&mm->page_table_lock); |
742 | } | |
743 | ||
aa2e878e | 744 | return 0; |
71e3aac0 AA |
745 | } |
746 | ||
cc5d462f | 747 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 748 | { |
cc5d462f | 749 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
750 | } |
751 | ||
752 | static inline struct page *alloc_hugepage_vma(int defrag, | |
753 | struct vm_area_struct *vma, | |
cc5d462f AK |
754 | unsigned long haddr, int nd, |
755 | gfp_t extra_gfp) | |
0bbbc0b3 | 756 | { |
cc5d462f | 757 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 758 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
759 | } |
760 | ||
761 | #ifndef CONFIG_NUMA | |
71e3aac0 AA |
762 | static inline struct page *alloc_hugepage(int defrag) |
763 | { | |
cc5d462f | 764 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), |
71e3aac0 AA |
765 | HPAGE_PMD_ORDER); |
766 | } | |
0bbbc0b3 | 767 | #endif |
71e3aac0 | 768 | |
3ea41e62 | 769 | static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
97ae1749 | 770 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd, |
5918d10a | 771 | struct page *zero_page) |
fc9fe822 KS |
772 | { |
773 | pmd_t entry; | |
3ea41e62 KS |
774 | if (!pmd_none(*pmd)) |
775 | return false; | |
5918d10a | 776 | entry = mk_pmd(zero_page, vma->vm_page_prot); |
fc9fe822 KS |
777 | entry = pmd_wrprotect(entry); |
778 | entry = pmd_mkhuge(entry); | |
6b0b50b0 | 779 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
fc9fe822 | 780 | set_pmd_at(mm, haddr, pmd, entry); |
fc9fe822 | 781 | mm->nr_ptes++; |
3ea41e62 | 782 | return true; |
fc9fe822 KS |
783 | } |
784 | ||
71e3aac0 AA |
785 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
786 | unsigned long address, pmd_t *pmd, | |
787 | unsigned int flags) | |
788 | { | |
789 | struct page *page; | |
790 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
71e3aac0 | 791 | |
128ec037 | 792 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) |
c0292554 | 793 | return VM_FAULT_FALLBACK; |
128ec037 KS |
794 | if (unlikely(anon_vma_prepare(vma))) |
795 | return VM_FAULT_OOM; | |
796 | if (unlikely(khugepaged_enter(vma))) | |
797 | return VM_FAULT_OOM; | |
798 | if (!(flags & FAULT_FLAG_WRITE) && | |
799 | transparent_hugepage_use_zero_page()) { | |
800 | pgtable_t pgtable; | |
801 | struct page *zero_page; | |
802 | bool set; | |
803 | pgtable = pte_alloc_one(mm, haddr); | |
804 | if (unlikely(!pgtable)) | |
ba76149f | 805 | return VM_FAULT_OOM; |
128ec037 KS |
806 | zero_page = get_huge_zero_page(); |
807 | if (unlikely(!zero_page)) { | |
808 | pte_free(mm, pgtable); | |
81ab4201 | 809 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 810 | return VM_FAULT_FALLBACK; |
b9bbfbe3 | 811 | } |
128ec037 KS |
812 | spin_lock(&mm->page_table_lock); |
813 | set = set_huge_zero_page(pgtable, mm, vma, haddr, pmd, | |
814 | zero_page); | |
815 | spin_unlock(&mm->page_table_lock); | |
816 | if (!set) { | |
817 | pte_free(mm, pgtable); | |
818 | put_huge_zero_page(); | |
edad9d2c | 819 | } |
edad9d2c | 820 | return 0; |
71e3aac0 | 821 | } |
128ec037 KS |
822 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
823 | vma, haddr, numa_node_id(), 0); | |
824 | if (unlikely(!page)) { | |
825 | count_vm_event(THP_FAULT_FALLBACK); | |
c0292554 | 826 | return VM_FAULT_FALLBACK; |
128ec037 | 827 | } |
128ec037 KS |
828 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
829 | put_page(page); | |
17766dde | 830 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 831 | return VM_FAULT_FALLBACK; |
128ec037 KS |
832 | } |
833 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, page))) { | |
834 | mem_cgroup_uncharge_page(page); | |
835 | put_page(page); | |
17766dde | 836 | count_vm_event(THP_FAULT_FALLBACK); |
c0292554 | 837 | return VM_FAULT_FALLBACK; |
128ec037 KS |
838 | } |
839 | ||
17766dde | 840 | count_vm_event(THP_FAULT_ALLOC); |
128ec037 | 841 | return 0; |
71e3aac0 AA |
842 | } |
843 | ||
844 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
845 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
846 | struct vm_area_struct *vma) | |
847 | { | |
848 | struct page *src_page; | |
849 | pmd_t pmd; | |
850 | pgtable_t pgtable; | |
851 | int ret; | |
852 | ||
853 | ret = -ENOMEM; | |
854 | pgtable = pte_alloc_one(dst_mm, addr); | |
855 | if (unlikely(!pgtable)) | |
856 | goto out; | |
857 | ||
858 | spin_lock(&dst_mm->page_table_lock); | |
859 | spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); | |
860 | ||
861 | ret = -EAGAIN; | |
862 | pmd = *src_pmd; | |
863 | if (unlikely(!pmd_trans_huge(pmd))) { | |
864 | pte_free(dst_mm, pgtable); | |
865 | goto out_unlock; | |
866 | } | |
fc9fe822 KS |
867 | /* |
868 | * mm->page_table_lock is enough to be sure that huge zero pmd is not | |
869 | * under splitting since we don't split the page itself, only pmd to | |
870 | * a page table. | |
871 | */ | |
872 | if (is_huge_zero_pmd(pmd)) { | |
5918d10a | 873 | struct page *zero_page; |
3ea41e62 | 874 | bool set; |
97ae1749 KS |
875 | /* |
876 | * get_huge_zero_page() will never allocate a new page here, | |
877 | * since we already have a zero page to copy. It just takes a | |
878 | * reference. | |
879 | */ | |
5918d10a | 880 | zero_page = get_huge_zero_page(); |
3ea41e62 | 881 | set = set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd, |
5918d10a | 882 | zero_page); |
3ea41e62 | 883 | BUG_ON(!set); /* unexpected !pmd_none(dst_pmd) */ |
fc9fe822 KS |
884 | ret = 0; |
885 | goto out_unlock; | |
886 | } | |
71e3aac0 AA |
887 | if (unlikely(pmd_trans_splitting(pmd))) { |
888 | /* split huge page running from under us */ | |
889 | spin_unlock(&src_mm->page_table_lock); | |
890 | spin_unlock(&dst_mm->page_table_lock); | |
891 | pte_free(dst_mm, pgtable); | |
892 | ||
893 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
894 | goto out; | |
895 | } | |
896 | src_page = pmd_page(pmd); | |
897 | VM_BUG_ON(!PageHead(src_page)); | |
898 | get_page(src_page); | |
899 | page_dup_rmap(src_page); | |
900 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
901 | ||
902 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
903 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
6b0b50b0 | 904 | pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); |
71e3aac0 | 905 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); |
1c641e84 | 906 | dst_mm->nr_ptes++; |
71e3aac0 AA |
907 | |
908 | ret = 0; | |
909 | out_unlock: | |
910 | spin_unlock(&src_mm->page_table_lock); | |
911 | spin_unlock(&dst_mm->page_table_lock); | |
912 | out: | |
913 | return ret; | |
914 | } | |
915 | ||
a1dd450b WD |
916 | void huge_pmd_set_accessed(struct mm_struct *mm, |
917 | struct vm_area_struct *vma, | |
918 | unsigned long address, | |
919 | pmd_t *pmd, pmd_t orig_pmd, | |
920 | int dirty) | |
921 | { | |
922 | pmd_t entry; | |
923 | unsigned long haddr; | |
924 | ||
925 | spin_lock(&mm->page_table_lock); | |
926 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
927 | goto unlock; | |
928 | ||
929 | entry = pmd_mkyoung(orig_pmd); | |
930 | haddr = address & HPAGE_PMD_MASK; | |
931 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) | |
932 | update_mmu_cache_pmd(vma, address, pmd); | |
933 | ||
934 | unlock: | |
935 | spin_unlock(&mm->page_table_lock); | |
936 | } | |
937 | ||
93b4796d KS |
938 | static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm, |
939 | struct vm_area_struct *vma, unsigned long address, | |
3ea41e62 | 940 | pmd_t *pmd, pmd_t orig_pmd, unsigned long haddr) |
93b4796d KS |
941 | { |
942 | pgtable_t pgtable; | |
943 | pmd_t _pmd; | |
944 | struct page *page; | |
945 | int i, ret = 0; | |
946 | unsigned long mmun_start; /* For mmu_notifiers */ | |
947 | unsigned long mmun_end; /* For mmu_notifiers */ | |
948 | ||
949 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
950 | if (!page) { | |
951 | ret |= VM_FAULT_OOM; | |
952 | goto out; | |
953 | } | |
954 | ||
955 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { | |
956 | put_page(page); | |
957 | ret |= VM_FAULT_OOM; | |
958 | goto out; | |
959 | } | |
960 | ||
961 | clear_user_highpage(page, address); | |
962 | __SetPageUptodate(page); | |
963 | ||
964 | mmun_start = haddr; | |
965 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
966 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
967 | ||
968 | spin_lock(&mm->page_table_lock); | |
3ea41e62 KS |
969 | if (unlikely(!pmd_same(*pmd, orig_pmd))) |
970 | goto out_free_page; | |
971 | ||
93b4796d KS |
972 | pmdp_clear_flush(vma, haddr, pmd); |
973 | /* leave pmd empty until pte is filled */ | |
974 | ||
6b0b50b0 | 975 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
93b4796d KS |
976 | pmd_populate(mm, &_pmd, pgtable); |
977 | ||
978 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
979 | pte_t *pte, entry; | |
980 | if (haddr == (address & PAGE_MASK)) { | |
981 | entry = mk_pte(page, vma->vm_page_prot); | |
982 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
983 | page_add_new_anon_rmap(page, vma, haddr); | |
984 | } else { | |
985 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
986 | entry = pte_mkspecial(entry); | |
987 | } | |
988 | pte = pte_offset_map(&_pmd, haddr); | |
989 | VM_BUG_ON(!pte_none(*pte)); | |
990 | set_pte_at(mm, haddr, pte, entry); | |
991 | pte_unmap(pte); | |
992 | } | |
993 | smp_wmb(); /* make pte visible before pmd */ | |
994 | pmd_populate(mm, pmd, pgtable); | |
995 | spin_unlock(&mm->page_table_lock); | |
97ae1749 | 996 | put_huge_zero_page(); |
93b4796d KS |
997 | inc_mm_counter(mm, MM_ANONPAGES); |
998 | ||
999 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1000 | ||
1001 | ret |= VM_FAULT_WRITE; | |
1002 | out: | |
1003 | return ret; | |
3ea41e62 KS |
1004 | out_free_page: |
1005 | spin_unlock(&mm->page_table_lock); | |
1006 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
1007 | mem_cgroup_uncharge_page(page); | |
1008 | put_page(page); | |
1009 | goto out; | |
93b4796d KS |
1010 | } |
1011 | ||
71e3aac0 AA |
1012 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
1013 | struct vm_area_struct *vma, | |
1014 | unsigned long address, | |
1015 | pmd_t *pmd, pmd_t orig_pmd, | |
1016 | struct page *page, | |
1017 | unsigned long haddr) | |
1018 | { | |
1019 | pgtable_t pgtable; | |
1020 | pmd_t _pmd; | |
1021 | int ret = 0, i; | |
1022 | struct page **pages; | |
2ec74c3e SG |
1023 | unsigned long mmun_start; /* For mmu_notifiers */ |
1024 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1025 | |
1026 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
1027 | GFP_KERNEL); | |
1028 | if (unlikely(!pages)) { | |
1029 | ret |= VM_FAULT_OOM; | |
1030 | goto out; | |
1031 | } | |
1032 | ||
1033 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
1034 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
1035 | __GFP_OTHER_NODE, | |
19ee151e | 1036 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
1037 | if (unlikely(!pages[i] || |
1038 | mem_cgroup_newpage_charge(pages[i], mm, | |
1039 | GFP_KERNEL))) { | |
1040 | if (pages[i]) | |
71e3aac0 | 1041 | put_page(pages[i]); |
b9bbfbe3 AA |
1042 | mem_cgroup_uncharge_start(); |
1043 | while (--i >= 0) { | |
1044 | mem_cgroup_uncharge_page(pages[i]); | |
1045 | put_page(pages[i]); | |
1046 | } | |
1047 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1048 | kfree(pages); |
1049 | ret |= VM_FAULT_OOM; | |
1050 | goto out; | |
1051 | } | |
1052 | } | |
1053 | ||
1054 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1055 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 1056 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
1057 | __SetPageUptodate(pages[i]); |
1058 | cond_resched(); | |
1059 | } | |
1060 | ||
2ec74c3e SG |
1061 | mmun_start = haddr; |
1062 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1063 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1064 | ||
71e3aac0 AA |
1065 | spin_lock(&mm->page_table_lock); |
1066 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1067 | goto out_free_pages; | |
1068 | VM_BUG_ON(!PageHead(page)); | |
1069 | ||
2ec74c3e | 1070 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1071 | /* leave pmd empty until pte is filled */ |
1072 | ||
6b0b50b0 | 1073 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
71e3aac0 AA |
1074 | pmd_populate(mm, &_pmd, pgtable); |
1075 | ||
1076 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
1077 | pte_t *pte, entry; | |
1078 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
1079 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1080 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
1081 | pte = pte_offset_map(&_pmd, haddr); | |
1082 | VM_BUG_ON(!pte_none(*pte)); | |
1083 | set_pte_at(mm, haddr, pte, entry); | |
1084 | pte_unmap(pte); | |
1085 | } | |
1086 | kfree(pages); | |
1087 | ||
71e3aac0 AA |
1088 | smp_wmb(); /* make pte visible before pmd */ |
1089 | pmd_populate(mm, pmd, pgtable); | |
1090 | page_remove_rmap(page); | |
1091 | spin_unlock(&mm->page_table_lock); | |
1092 | ||
2ec74c3e SG |
1093 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1094 | ||
71e3aac0 AA |
1095 | ret |= VM_FAULT_WRITE; |
1096 | put_page(page); | |
1097 | ||
1098 | out: | |
1099 | return ret; | |
1100 | ||
1101 | out_free_pages: | |
1102 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1103 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
1104 | mem_cgroup_uncharge_start(); |
1105 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1106 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 1107 | put_page(pages[i]); |
b9bbfbe3 AA |
1108 | } |
1109 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1110 | kfree(pages); |
1111 | goto out; | |
1112 | } | |
1113 | ||
1114 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1115 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
1116 | { | |
1117 | int ret = 0; | |
93b4796d | 1118 | struct page *page = NULL, *new_page; |
71e3aac0 | 1119 | unsigned long haddr; |
2ec74c3e SG |
1120 | unsigned long mmun_start; /* For mmu_notifiers */ |
1121 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1122 | |
1123 | VM_BUG_ON(!vma->anon_vma); | |
93b4796d KS |
1124 | haddr = address & HPAGE_PMD_MASK; |
1125 | if (is_huge_zero_pmd(orig_pmd)) | |
1126 | goto alloc; | |
71e3aac0 AA |
1127 | spin_lock(&mm->page_table_lock); |
1128 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1129 | goto out_unlock; | |
1130 | ||
1131 | page = pmd_page(orig_pmd); | |
1132 | VM_BUG_ON(!PageCompound(page) || !PageHead(page)); | |
71e3aac0 AA |
1133 | if (page_mapcount(page) == 1) { |
1134 | pmd_t entry; | |
1135 | entry = pmd_mkyoung(orig_pmd); | |
1136 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
1137 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 1138 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
1139 | ret |= VM_FAULT_WRITE; |
1140 | goto out_unlock; | |
1141 | } | |
1142 | get_page(page); | |
1143 | spin_unlock(&mm->page_table_lock); | |
93b4796d | 1144 | alloc: |
71e3aac0 AA |
1145 | if (transparent_hugepage_enabled(vma) && |
1146 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 1147 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 1148 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
1149 | else |
1150 | new_page = NULL; | |
1151 | ||
1152 | if (unlikely(!new_page)) { | |
93b4796d KS |
1153 | if (is_huge_zero_pmd(orig_pmd)) { |
1154 | ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, | |
3ea41e62 | 1155 | address, pmd, orig_pmd, haddr); |
93b4796d KS |
1156 | } else { |
1157 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, | |
1158 | pmd, orig_pmd, page, haddr); | |
1159 | if (ret & VM_FAULT_OOM) | |
1160 | split_huge_page(page); | |
1161 | put_page(page); | |
1162 | } | |
17766dde | 1163 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
1164 | goto out; |
1165 | } | |
1166 | ||
b9bbfbe3 AA |
1167 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
1168 | put_page(new_page); | |
93b4796d KS |
1169 | if (page) { |
1170 | split_huge_page(page); | |
1171 | put_page(page); | |
1172 | } | |
17766dde | 1173 | count_vm_event(THP_FAULT_FALLBACK); |
b9bbfbe3 AA |
1174 | ret |= VM_FAULT_OOM; |
1175 | goto out; | |
1176 | } | |
1177 | ||
17766dde DR |
1178 | count_vm_event(THP_FAULT_ALLOC); |
1179 | ||
93b4796d KS |
1180 | if (is_huge_zero_pmd(orig_pmd)) |
1181 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); | |
1182 | else | |
1183 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1184 | __SetPageUptodate(new_page); |
1185 | ||
2ec74c3e SG |
1186 | mmun_start = haddr; |
1187 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1188 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1189 | ||
71e3aac0 | 1190 | spin_lock(&mm->page_table_lock); |
93b4796d KS |
1191 | if (page) |
1192 | put_page(page); | |
b9bbfbe3 | 1193 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
6f60b69d | 1194 | spin_unlock(&mm->page_table_lock); |
b9bbfbe3 | 1195 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 1196 | put_page(new_page); |
2ec74c3e | 1197 | goto out_mn; |
b9bbfbe3 | 1198 | } else { |
71e3aac0 | 1199 | pmd_t entry; |
3122359a KS |
1200 | entry = mk_huge_pmd(new_page, vma->vm_page_prot); |
1201 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
2ec74c3e | 1202 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1203 | page_add_new_anon_rmap(new_page, vma, haddr); |
1204 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 1205 | update_mmu_cache_pmd(vma, address, pmd); |
97ae1749 | 1206 | if (is_huge_zero_pmd(orig_pmd)) { |
93b4796d | 1207 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
97ae1749 KS |
1208 | put_huge_zero_page(); |
1209 | } else { | |
93b4796d KS |
1210 | VM_BUG_ON(!PageHead(page)); |
1211 | page_remove_rmap(page); | |
1212 | put_page(page); | |
1213 | } | |
71e3aac0 AA |
1214 | ret |= VM_FAULT_WRITE; |
1215 | } | |
71e3aac0 | 1216 | spin_unlock(&mm->page_table_lock); |
2ec74c3e SG |
1217 | out_mn: |
1218 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
1219 | out: |
1220 | return ret; | |
2ec74c3e SG |
1221 | out_unlock: |
1222 | spin_unlock(&mm->page_table_lock); | |
1223 | return ret; | |
71e3aac0 AA |
1224 | } |
1225 | ||
b676b293 | 1226 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1227 | unsigned long addr, |
1228 | pmd_t *pmd, | |
1229 | unsigned int flags) | |
1230 | { | |
b676b293 | 1231 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1232 | struct page *page = NULL; |
1233 | ||
1234 | assert_spin_locked(&mm->page_table_lock); | |
1235 | ||
1236 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1237 | goto out; | |
1238 | ||
85facf25 KS |
1239 | /* Avoid dumping huge zero page */ |
1240 | if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd)) | |
1241 | return ERR_PTR(-EFAULT); | |
1242 | ||
71e3aac0 AA |
1243 | page = pmd_page(*pmd); |
1244 | VM_BUG_ON(!PageHead(page)); | |
1245 | if (flags & FOLL_TOUCH) { | |
1246 | pmd_t _pmd; | |
1247 | /* | |
1248 | * We should set the dirty bit only for FOLL_WRITE but | |
1249 | * for now the dirty bit in the pmd is meaningless. | |
1250 | * And if the dirty bit will become meaningful and | |
1251 | * we'll only set it with FOLL_WRITE, an atomic | |
1252 | * set_bit will be required on the pmd to set the | |
1253 | * young bit, instead of the current set_pmd_at. | |
1254 | */ | |
1255 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
8663890a AK |
1256 | if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK, |
1257 | pmd, _pmd, 1)) | |
1258 | update_mmu_cache_pmd(vma, addr, pmd); | |
71e3aac0 | 1259 | } |
b676b293 DR |
1260 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1261 | if (page->mapping && trylock_page(page)) { | |
1262 | lru_add_drain(); | |
1263 | if (page->mapping) | |
1264 | mlock_vma_page(page); | |
1265 | unlock_page(page); | |
1266 | } | |
1267 | } | |
71e3aac0 AA |
1268 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
1269 | VM_BUG_ON(!PageCompound(page)); | |
1270 | if (flags & FOLL_GET) | |
70b50f94 | 1271 | get_page_foll(page); |
71e3aac0 AA |
1272 | |
1273 | out: | |
1274 | return page; | |
1275 | } | |
1276 | ||
d10e63f2 | 1277 | /* NUMA hinting page fault entry point for trans huge pmds */ |
4daae3b4 MG |
1278 | int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1279 | unsigned long addr, pmd_t pmd, pmd_t *pmdp) | |
d10e63f2 | 1280 | { |
587fe586 | 1281 | struct anon_vma *anon_vma = NULL; |
b32967ff | 1282 | struct page *page; |
d10e63f2 | 1283 | unsigned long haddr = addr & HPAGE_PMD_MASK; |
c61109e3 | 1284 | int page_nid = -1, this_nid = numa_node_id(); |
4daae3b4 | 1285 | int target_nid; |
c61109e3 MG |
1286 | bool page_locked; |
1287 | bool migrated = false; | |
d10e63f2 MG |
1288 | |
1289 | spin_lock(&mm->page_table_lock); | |
1290 | if (unlikely(!pmd_same(pmd, *pmdp))) | |
1291 | goto out_unlock; | |
1292 | ||
1293 | page = pmd_page(pmd); | |
c61109e3 | 1294 | page_nid = page_to_nid(page); |
03c5a6e1 | 1295 | count_vm_numa_event(NUMA_HINT_FAULTS); |
c61109e3 | 1296 | if (page_nid == this_nid) |
03c5a6e1 | 1297 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
4daae3b4 | 1298 | |
42836f5f MG |
1299 | /* |
1300 | * Acquire the page lock to serialise THP migrations but avoid dropping | |
1301 | * page_table_lock if at all possible | |
1302 | */ | |
587fe586 MG |
1303 | page_locked = trylock_page(page); |
1304 | target_nid = mpol_misplaced(page, vma, haddr); | |
1305 | if (target_nid == -1) { | |
1306 | /* If the page was locked, there are no parallel migrations */ | |
3f926ab9 | 1307 | if (page_locked) |
587fe586 | 1308 | goto clear_pmdnuma; |
4daae3b4 | 1309 | |
3f926ab9 MG |
1310 | /* |
1311 | * Otherwise wait for potential migrations and retry. We do | |
1312 | * relock and check_same as the page may no longer be mapped. | |
1313 | * As the fault is being retried, do not account for it. | |
1314 | */ | |
587fe586 MG |
1315 | spin_unlock(&mm->page_table_lock); |
1316 | wait_on_page_locked(page); | |
3f926ab9 | 1317 | page_nid = -1; |
587fe586 MG |
1318 | goto out; |
1319 | } | |
1320 | ||
1321 | /* Page is misplaced, serialise migrations and parallel THP splits */ | |
1322 | get_page(page); | |
b32967ff | 1323 | spin_unlock(&mm->page_table_lock); |
3f926ab9 | 1324 | if (!page_locked) |
587fe586 | 1325 | lock_page(page); |
587fe586 | 1326 | anon_vma = page_lock_anon_vma_read(page); |
4daae3b4 | 1327 | |
b32967ff | 1328 | /* Confirm the PTE did not while locked */ |
4daae3b4 | 1329 | spin_lock(&mm->page_table_lock); |
b32967ff MG |
1330 | if (unlikely(!pmd_same(pmd, *pmdp))) { |
1331 | unlock_page(page); | |
1332 | put_page(page); | |
3f926ab9 | 1333 | page_nid = -1; |
4daae3b4 | 1334 | goto out_unlock; |
b32967ff | 1335 | } |
42836f5f | 1336 | |
3f926ab9 MG |
1337 | /* |
1338 | * Migrate the THP to the requested node, returns with page unlocked | |
1339 | * and pmd_numa cleared. | |
1340 | */ | |
42836f5f | 1341 | spin_unlock(&mm->page_table_lock); |
b32967ff | 1342 | migrated = migrate_misplaced_transhuge_page(mm, vma, |
340ef390 | 1343 | pmdp, pmd, addr, page, target_nid); |
c61109e3 MG |
1344 | if (migrated) |
1345 | page_nid = target_nid; | |
b32967ff | 1346 | |
c61109e3 | 1347 | goto out; |
b32967ff | 1348 | clear_pmdnuma: |
3f926ab9 | 1349 | BUG_ON(!PageLocked(page)); |
d10e63f2 MG |
1350 | pmd = pmd_mknonnuma(pmd); |
1351 | set_pmd_at(mm, haddr, pmdp, pmd); | |
1352 | VM_BUG_ON(pmd_numa(*pmdp)); | |
1353 | update_mmu_cache_pmd(vma, addr, pmdp); | |
3f926ab9 | 1354 | unlock_page(page); |
d10e63f2 MG |
1355 | out_unlock: |
1356 | spin_unlock(&mm->page_table_lock); | |
587fe586 MG |
1357 | |
1358 | out: | |
1359 | if (anon_vma) | |
1360 | page_unlock_anon_vma_read(anon_vma); | |
1361 | ||
c61109e3 MG |
1362 | if (page_nid != -1) |
1363 | task_numa_fault(page_nid, HPAGE_PMD_NR, migrated); | |
1364 | ||
d10e63f2 MG |
1365 | return 0; |
1366 | } | |
1367 | ||
71e3aac0 | 1368 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1369 | pmd_t *pmd, unsigned long addr) |
71e3aac0 AA |
1370 | { |
1371 | int ret = 0; | |
1372 | ||
025c5b24 NH |
1373 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1374 | struct page *page; | |
1375 | pgtable_t pgtable; | |
f5c8ad47 | 1376 | pmd_t orig_pmd; |
a6bf2bb0 AK |
1377 | /* |
1378 | * For architectures like ppc64 we look at deposited pgtable | |
1379 | * when calling pmdp_get_and_clear. So do the | |
1380 | * pgtable_trans_huge_withdraw after finishing pmdp related | |
1381 | * operations. | |
1382 | */ | |
f5c8ad47 | 1383 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
025c5b24 | 1384 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
a6bf2bb0 | 1385 | pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); |
479f0abb KS |
1386 | if (is_huge_zero_pmd(orig_pmd)) { |
1387 | tlb->mm->nr_ptes--; | |
1388 | spin_unlock(&tlb->mm->page_table_lock); | |
97ae1749 | 1389 | put_huge_zero_page(); |
479f0abb KS |
1390 | } else { |
1391 | page = pmd_page(orig_pmd); | |
1392 | page_remove_rmap(page); | |
1393 | VM_BUG_ON(page_mapcount(page) < 0); | |
1394 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); | |
1395 | VM_BUG_ON(!PageHead(page)); | |
1396 | tlb->mm->nr_ptes--; | |
1397 | spin_unlock(&tlb->mm->page_table_lock); | |
1398 | tlb_remove_page(tlb, page); | |
1399 | } | |
025c5b24 NH |
1400 | pte_free(tlb->mm, pgtable); |
1401 | ret = 1; | |
1402 | } | |
71e3aac0 AA |
1403 | return ret; |
1404 | } | |
1405 | ||
0ca1634d JW |
1406 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1407 | unsigned long addr, unsigned long end, | |
1408 | unsigned char *vec) | |
1409 | { | |
1410 | int ret = 0; | |
1411 | ||
025c5b24 NH |
1412 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1413 | /* | |
1414 | * All logical pages in the range are present | |
1415 | * if backed by a huge page. | |
1416 | */ | |
0ca1634d | 1417 | spin_unlock(&vma->vm_mm->page_table_lock); |
025c5b24 NH |
1418 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1419 | ret = 1; | |
1420 | } | |
0ca1634d JW |
1421 | |
1422 | return ret; | |
1423 | } | |
1424 | ||
37a1c49a AA |
1425 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1426 | unsigned long old_addr, | |
1427 | unsigned long new_addr, unsigned long old_end, | |
1428 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1429 | { | |
1430 | int ret = 0; | |
1431 | pmd_t pmd; | |
1432 | ||
1433 | struct mm_struct *mm = vma->vm_mm; | |
1434 | ||
1435 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1436 | (new_addr & ~HPAGE_PMD_MASK) || | |
1437 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1438 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1439 | goto out; | |
1440 | ||
1441 | /* | |
1442 | * The destination pmd shouldn't be established, free_pgtables() | |
1443 | * should have release it. | |
1444 | */ | |
1445 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1446 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1447 | goto out; | |
1448 | } | |
1449 | ||
025c5b24 NH |
1450 | ret = __pmd_trans_huge_lock(old_pmd, vma); |
1451 | if (ret == 1) { | |
1452 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); | |
1453 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
0f8975ec | 1454 | set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); |
37a1c49a AA |
1455 | spin_unlock(&mm->page_table_lock); |
1456 | } | |
1457 | out: | |
1458 | return ret; | |
1459 | } | |
1460 | ||
cd7548ab | 1461 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
4b10e7d5 | 1462 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1463 | { |
1464 | struct mm_struct *mm = vma->vm_mm; | |
1465 | int ret = 0; | |
1466 | ||
025c5b24 NH |
1467 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1468 | pmd_t entry; | |
1469 | entry = pmdp_get_and_clear(mm, addr, pmd); | |
a4f1de17 | 1470 | if (!prot_numa) { |
4b10e7d5 | 1471 | entry = pmd_modify(entry, newprot); |
a4f1de17 HD |
1472 | BUG_ON(pmd_write(entry)); |
1473 | } else { | |
4b10e7d5 MG |
1474 | struct page *page = pmd_page(*pmd); |
1475 | ||
1476 | /* only check non-shared pages */ | |
1477 | if (page_mapcount(page) == 1 && | |
1478 | !pmd_numa(*pmd)) { | |
1479 | entry = pmd_mknuma(entry); | |
1480 | } | |
1481 | } | |
025c5b24 NH |
1482 | set_pmd_at(mm, addr, pmd, entry); |
1483 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1484 | ret = 1; | |
1485 | } | |
1486 | ||
1487 | return ret; | |
1488 | } | |
1489 | ||
1490 | /* | |
1491 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1492 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1493 | * | |
1494 | * Note that if it returns 1, this routine returns without unlocking page | |
1495 | * table locks. So callers must unlock them. | |
1496 | */ | |
1497 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) | |
1498 | { | |
1499 | spin_lock(&vma->vm_mm->page_table_lock); | |
cd7548ab JW |
1500 | if (likely(pmd_trans_huge(*pmd))) { |
1501 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
025c5b24 | 1502 | spin_unlock(&vma->vm_mm->page_table_lock); |
cd7548ab | 1503 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1504 | return -1; |
cd7548ab | 1505 | } else { |
025c5b24 NH |
1506 | /* Thp mapped by 'pmd' is stable, so we can |
1507 | * handle it as it is. */ | |
1508 | return 1; | |
cd7548ab | 1509 | } |
025c5b24 NH |
1510 | } |
1511 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1512 | return 0; | |
cd7548ab JW |
1513 | } |
1514 | ||
71e3aac0 AA |
1515 | pmd_t *page_check_address_pmd(struct page *page, |
1516 | struct mm_struct *mm, | |
1517 | unsigned long address, | |
1518 | enum page_check_address_pmd_flag flag) | |
1519 | { | |
71e3aac0 AA |
1520 | pmd_t *pmd, *ret = NULL; |
1521 | ||
1522 | if (address & ~HPAGE_PMD_MASK) | |
1523 | goto out; | |
1524 | ||
6219049a BL |
1525 | pmd = mm_find_pmd(mm, address); |
1526 | if (!pmd) | |
71e3aac0 | 1527 | goto out; |
71e3aac0 AA |
1528 | if (pmd_none(*pmd)) |
1529 | goto out; | |
1530 | if (pmd_page(*pmd) != page) | |
1531 | goto out; | |
94fcc585 AA |
1532 | /* |
1533 | * split_vma() may create temporary aliased mappings. There is | |
1534 | * no risk as long as all huge pmd are found and have their | |
1535 | * splitting bit set before __split_huge_page_refcount | |
1536 | * runs. Finding the same huge pmd more than once during the | |
1537 | * same rmap walk is not a problem. | |
1538 | */ | |
1539 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1540 | pmd_trans_splitting(*pmd)) | |
1541 | goto out; | |
71e3aac0 AA |
1542 | if (pmd_trans_huge(*pmd)) { |
1543 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1544 | !pmd_trans_splitting(*pmd)); | |
1545 | ret = pmd; | |
1546 | } | |
1547 | out: | |
1548 | return ret; | |
1549 | } | |
1550 | ||
1551 | static int __split_huge_page_splitting(struct page *page, | |
1552 | struct vm_area_struct *vma, | |
1553 | unsigned long address) | |
1554 | { | |
1555 | struct mm_struct *mm = vma->vm_mm; | |
1556 | pmd_t *pmd; | |
1557 | int ret = 0; | |
2ec74c3e SG |
1558 | /* For mmu_notifiers */ |
1559 | const unsigned long mmun_start = address; | |
1560 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1561 | |
2ec74c3e | 1562 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1563 | spin_lock(&mm->page_table_lock); |
1564 | pmd = page_check_address_pmd(page, mm, address, | |
1565 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); | |
1566 | if (pmd) { | |
1567 | /* | |
1568 | * We can't temporarily set the pmd to null in order | |
1569 | * to split it, the pmd must remain marked huge at all | |
1570 | * times or the VM won't take the pmd_trans_huge paths | |
5a505085 | 1571 | * and it won't wait on the anon_vma->root->rwsem to |
71e3aac0 AA |
1572 | * serialize against split_huge_page*. |
1573 | */ | |
2ec74c3e | 1574 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 AA |
1575 | ret = 1; |
1576 | } | |
1577 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1578 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1579 | |
1580 | return ret; | |
1581 | } | |
1582 | ||
5bc7b8ac SL |
1583 | static void __split_huge_page_refcount(struct page *page, |
1584 | struct list_head *list) | |
71e3aac0 AA |
1585 | { |
1586 | int i; | |
71e3aac0 | 1587 | struct zone *zone = page_zone(page); |
fa9add64 | 1588 | struct lruvec *lruvec; |
70b50f94 | 1589 | int tail_count = 0; |
71e3aac0 AA |
1590 | |
1591 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1592 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1593 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1594 | ||
71e3aac0 | 1595 | compound_lock(page); |
e94c8a9c KH |
1596 | /* complete memcg works before add pages to LRU */ |
1597 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1598 | |
45676885 | 1599 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1600 | struct page *page_tail = page + i; |
1601 | ||
70b50f94 AA |
1602 | /* tail_page->_mapcount cannot change */ |
1603 | BUG_ON(page_mapcount(page_tail) < 0); | |
1604 | tail_count += page_mapcount(page_tail); | |
1605 | /* check for overflow */ | |
1606 | BUG_ON(tail_count < 0); | |
1607 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1608 | /* | |
1609 | * tail_page->_count is zero and not changing from | |
1610 | * under us. But get_page_unless_zero() may be running | |
1611 | * from under us on the tail_page. If we used | |
1612 | * atomic_set() below instead of atomic_add(), we | |
1613 | * would then run atomic_set() concurrently with | |
1614 | * get_page_unless_zero(), and atomic_set() is | |
1615 | * implemented in C not using locked ops. spin_unlock | |
1616 | * on x86 sometime uses locked ops because of PPro | |
1617 | * errata 66, 92, so unless somebody can guarantee | |
1618 | * atomic_set() here would be safe on all archs (and | |
1619 | * not only on x86), it's safer to use atomic_add(). | |
1620 | */ | |
1621 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1622 | &page_tail->_count); | |
71e3aac0 AA |
1623 | |
1624 | /* after clearing PageTail the gup refcount can be released */ | |
1625 | smp_mb(); | |
1626 | ||
a6d30ddd JD |
1627 | /* |
1628 | * retain hwpoison flag of the poisoned tail page: | |
1629 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1630 | * by the memory-failure. | |
1631 | */ | |
1632 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1633 | page_tail->flags |= (page->flags & |
1634 | ((1L << PG_referenced) | | |
1635 | (1L << PG_swapbacked) | | |
1636 | (1L << PG_mlocked) | | |
e180cf80 KS |
1637 | (1L << PG_uptodate) | |
1638 | (1L << PG_active) | | |
1639 | (1L << PG_unevictable))); | |
71e3aac0 AA |
1640 | page_tail->flags |= (1L << PG_dirty); |
1641 | ||
70b50f94 | 1642 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1643 | smp_wmb(); |
1644 | ||
1645 | /* | |
1646 | * __split_huge_page_splitting() already set the | |
1647 | * splitting bit in all pmd that could map this | |
1648 | * hugepage, that will ensure no CPU can alter the | |
1649 | * mapcount on the head page. The mapcount is only | |
1650 | * accounted in the head page and it has to be | |
1651 | * transferred to all tail pages in the below code. So | |
1652 | * for this code to be safe, the split the mapcount | |
1653 | * can't change. But that doesn't mean userland can't | |
1654 | * keep changing and reading the page contents while | |
1655 | * we transfer the mapcount, so the pmd splitting | |
1656 | * status is achieved setting a reserved bit in the | |
1657 | * pmd, not by clearing the present bit. | |
1658 | */ | |
71e3aac0 AA |
1659 | page_tail->_mapcount = page->_mapcount; |
1660 | ||
1661 | BUG_ON(page_tail->mapping); | |
1662 | page_tail->mapping = page->mapping; | |
1663 | ||
45676885 | 1664 | page_tail->index = page->index + i; |
22b751c3 | 1665 | page_nid_xchg_last(page_tail, page_nid_last(page)); |
71e3aac0 AA |
1666 | |
1667 | BUG_ON(!PageAnon(page_tail)); | |
1668 | BUG_ON(!PageUptodate(page_tail)); | |
1669 | BUG_ON(!PageDirty(page_tail)); | |
1670 | BUG_ON(!PageSwapBacked(page_tail)); | |
1671 | ||
5bc7b8ac | 1672 | lru_add_page_tail(page, page_tail, lruvec, list); |
71e3aac0 | 1673 | } |
70b50f94 AA |
1674 | atomic_sub(tail_count, &page->_count); |
1675 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1676 | |
fa9add64 | 1677 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 | 1678 | |
71e3aac0 AA |
1679 | ClearPageCompound(page); |
1680 | compound_unlock(page); | |
1681 | spin_unlock_irq(&zone->lru_lock); | |
1682 | ||
1683 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1684 | struct page *page_tail = page + i; | |
1685 | BUG_ON(page_count(page_tail) <= 0); | |
1686 | /* | |
1687 | * Tail pages may be freed if there wasn't any mapping | |
1688 | * like if add_to_swap() is running on a lru page that | |
1689 | * had its mapping zapped. And freeing these pages | |
1690 | * requires taking the lru_lock so we do the put_page | |
1691 | * of the tail pages after the split is complete. | |
1692 | */ | |
1693 | put_page(page_tail); | |
1694 | } | |
1695 | ||
1696 | /* | |
1697 | * Only the head page (now become a regular page) is required | |
1698 | * to be pinned by the caller. | |
1699 | */ | |
1700 | BUG_ON(page_count(page) <= 0); | |
1701 | } | |
1702 | ||
1703 | static int __split_huge_page_map(struct page *page, | |
1704 | struct vm_area_struct *vma, | |
1705 | unsigned long address) | |
1706 | { | |
1707 | struct mm_struct *mm = vma->vm_mm; | |
1708 | pmd_t *pmd, _pmd; | |
1709 | int ret = 0, i; | |
1710 | pgtable_t pgtable; | |
1711 | unsigned long haddr; | |
1712 | ||
1713 | spin_lock(&mm->page_table_lock); | |
1714 | pmd = page_check_address_pmd(page, mm, address, | |
1715 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); | |
1716 | if (pmd) { | |
6b0b50b0 | 1717 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
71e3aac0 AA |
1718 | pmd_populate(mm, &_pmd, pgtable); |
1719 | ||
e3ebcf64 GS |
1720 | haddr = address; |
1721 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1722 | pte_t *pte, entry; |
1723 | BUG_ON(PageCompound(page+i)); | |
1724 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1725 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1726 | if (!pmd_write(*pmd)) | |
1727 | entry = pte_wrprotect(entry); | |
1728 | else | |
1729 | BUG_ON(page_mapcount(page) != 1); | |
1730 | if (!pmd_young(*pmd)) | |
1731 | entry = pte_mkold(entry); | |
1ba6e0b5 AA |
1732 | if (pmd_numa(*pmd)) |
1733 | entry = pte_mknuma(entry); | |
71e3aac0 AA |
1734 | pte = pte_offset_map(&_pmd, haddr); |
1735 | BUG_ON(!pte_none(*pte)); | |
1736 | set_pte_at(mm, haddr, pte, entry); | |
1737 | pte_unmap(pte); | |
1738 | } | |
1739 | ||
71e3aac0 AA |
1740 | smp_wmb(); /* make pte visible before pmd */ |
1741 | /* | |
1742 | * Up to this point the pmd is present and huge and | |
1743 | * userland has the whole access to the hugepage | |
1744 | * during the split (which happens in place). If we | |
1745 | * overwrite the pmd with the not-huge version | |
1746 | * pointing to the pte here (which of course we could | |
1747 | * if all CPUs were bug free), userland could trigger | |
1748 | * a small page size TLB miss on the small sized TLB | |
1749 | * while the hugepage TLB entry is still established | |
1750 | * in the huge TLB. Some CPU doesn't like that. See | |
1751 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1752 | * Erratum 383 on page 93. Intel should be safe but is | |
1753 | * also warns that it's only safe if the permission | |
1754 | * and cache attributes of the two entries loaded in | |
1755 | * the two TLB is identical (which should be the case | |
1756 | * here). But it is generally safer to never allow | |
1757 | * small and huge TLB entries for the same virtual | |
1758 | * address to be loaded simultaneously. So instead of | |
1759 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1760 | * mark the current pmd notpresent (atomically because | |
1761 | * here the pmd_trans_huge and pmd_trans_splitting | |
1762 | * must remain set at all times on the pmd until the | |
1763 | * split is complete for this pmd), then we flush the | |
1764 | * SMP TLB and finally we write the non-huge version | |
1765 | * of the pmd entry with pmd_populate. | |
1766 | */ | |
46dcde73 | 1767 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1768 | pmd_populate(mm, pmd, pgtable); |
1769 | ret = 1; | |
1770 | } | |
1771 | spin_unlock(&mm->page_table_lock); | |
1772 | ||
1773 | return ret; | |
1774 | } | |
1775 | ||
5a505085 | 1776 | /* must be called with anon_vma->root->rwsem held */ |
71e3aac0 | 1777 | static void __split_huge_page(struct page *page, |
5bc7b8ac SL |
1778 | struct anon_vma *anon_vma, |
1779 | struct list_head *list) | |
71e3aac0 AA |
1780 | { |
1781 | int mapcount, mapcount2; | |
bf181b9f | 1782 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1783 | struct anon_vma_chain *avc; |
1784 | ||
1785 | BUG_ON(!PageHead(page)); | |
1786 | BUG_ON(PageTail(page)); | |
1787 | ||
1788 | mapcount = 0; | |
bf181b9f | 1789 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1790 | struct vm_area_struct *vma = avc->vma; |
1791 | unsigned long addr = vma_address(page, vma); | |
1792 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1793 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1794 | } | |
05759d38 AA |
1795 | /* |
1796 | * It is critical that new vmas are added to the tail of the | |
1797 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1798 | * and establishes a child pmd before | |
1799 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1800 | * we fail to prevent copy_huge_pmd() from running until the | |
1801 | * whole __split_huge_page() is complete), we will still see | |
1802 | * the newly established pmd of the child later during the | |
1803 | * walk, to be able to set it as pmd_trans_splitting too. | |
1804 | */ | |
1805 | if (mapcount != page_mapcount(page)) | |
1806 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1807 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1808 | BUG_ON(mapcount != page_mapcount(page)); |
1809 | ||
5bc7b8ac | 1810 | __split_huge_page_refcount(page, list); |
71e3aac0 AA |
1811 | |
1812 | mapcount2 = 0; | |
bf181b9f | 1813 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1814 | struct vm_area_struct *vma = avc->vma; |
1815 | unsigned long addr = vma_address(page, vma); | |
1816 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1817 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1818 | } | |
05759d38 AA |
1819 | if (mapcount != mapcount2) |
1820 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1821 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1822 | BUG_ON(mapcount != mapcount2); |
1823 | } | |
1824 | ||
5bc7b8ac SL |
1825 | /* |
1826 | * Split a hugepage into normal pages. This doesn't change the position of head | |
1827 | * page. If @list is null, tail pages will be added to LRU list, otherwise, to | |
1828 | * @list. Both head page and tail pages will inherit mapping, flags, and so on | |
1829 | * from the hugepage. | |
1830 | * Return 0 if the hugepage is split successfully otherwise return 1. | |
1831 | */ | |
1832 | int split_huge_page_to_list(struct page *page, struct list_head *list) | |
71e3aac0 AA |
1833 | { |
1834 | struct anon_vma *anon_vma; | |
1835 | int ret = 1; | |
1836 | ||
5918d10a | 1837 | BUG_ON(is_huge_zero_page(page)); |
71e3aac0 | 1838 | BUG_ON(!PageAnon(page)); |
062f1af2 MG |
1839 | |
1840 | /* | |
1841 | * The caller does not necessarily hold an mmap_sem that would prevent | |
1842 | * the anon_vma disappearing so we first we take a reference to it | |
1843 | * and then lock the anon_vma for write. This is similar to | |
1844 | * page_lock_anon_vma_read except the write lock is taken to serialise | |
1845 | * against parallel split or collapse operations. | |
1846 | */ | |
1847 | anon_vma = page_get_anon_vma(page); | |
71e3aac0 AA |
1848 | if (!anon_vma) |
1849 | goto out; | |
062f1af2 MG |
1850 | anon_vma_lock_write(anon_vma); |
1851 | ||
71e3aac0 AA |
1852 | ret = 0; |
1853 | if (!PageCompound(page)) | |
1854 | goto out_unlock; | |
1855 | ||
1856 | BUG_ON(!PageSwapBacked(page)); | |
5bc7b8ac | 1857 | __split_huge_page(page, anon_vma, list); |
81ab4201 | 1858 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1859 | |
1860 | BUG_ON(PageCompound(page)); | |
1861 | out_unlock: | |
08b52706 | 1862 | anon_vma_unlock_write(anon_vma); |
062f1af2 | 1863 | put_anon_vma(anon_vma); |
71e3aac0 AA |
1864 | out: |
1865 | return ret; | |
1866 | } | |
1867 | ||
4b6e1e37 | 1868 | #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) |
78f11a25 | 1869 | |
60ab3244 AA |
1870 | int hugepage_madvise(struct vm_area_struct *vma, |
1871 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1872 | { |
8e72033f GS |
1873 | struct mm_struct *mm = vma->vm_mm; |
1874 | ||
a664b2d8 AA |
1875 | switch (advice) { |
1876 | case MADV_HUGEPAGE: | |
1877 | /* | |
1878 | * Be somewhat over-protective like KSM for now! | |
1879 | */ | |
78f11a25 | 1880 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1881 | return -EINVAL; |
8e72033f GS |
1882 | if (mm->def_flags & VM_NOHUGEPAGE) |
1883 | return -EINVAL; | |
a664b2d8 AA |
1884 | *vm_flags &= ~VM_NOHUGEPAGE; |
1885 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1886 | /* |
1887 | * If the vma become good for khugepaged to scan, | |
1888 | * register it here without waiting a page fault that | |
1889 | * may not happen any time soon. | |
1890 | */ | |
1891 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1892 | return -ENOMEM; | |
a664b2d8 AA |
1893 | break; |
1894 | case MADV_NOHUGEPAGE: | |
1895 | /* | |
1896 | * Be somewhat over-protective like KSM for now! | |
1897 | */ | |
78f11a25 | 1898 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1899 | return -EINVAL; |
1900 | *vm_flags &= ~VM_HUGEPAGE; | |
1901 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1902 | /* |
1903 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
1904 | * this vma even if we leave the mm registered in khugepaged if | |
1905 | * it got registered before VM_NOHUGEPAGE was set. | |
1906 | */ | |
a664b2d8 AA |
1907 | break; |
1908 | } | |
0af4e98b AA |
1909 | |
1910 | return 0; | |
1911 | } | |
1912 | ||
ba76149f AA |
1913 | static int __init khugepaged_slab_init(void) |
1914 | { | |
1915 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
1916 | sizeof(struct mm_slot), | |
1917 | __alignof__(struct mm_slot), 0, NULL); | |
1918 | if (!mm_slot_cache) | |
1919 | return -ENOMEM; | |
1920 | ||
1921 | return 0; | |
1922 | } | |
1923 | ||
ba76149f AA |
1924 | static inline struct mm_slot *alloc_mm_slot(void) |
1925 | { | |
1926 | if (!mm_slot_cache) /* initialization failed */ | |
1927 | return NULL; | |
1928 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
1929 | } | |
1930 | ||
1931 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
1932 | { | |
1933 | kmem_cache_free(mm_slot_cache, mm_slot); | |
1934 | } | |
1935 | ||
ba76149f AA |
1936 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) |
1937 | { | |
1938 | struct mm_slot *mm_slot; | |
ba76149f | 1939 | |
b67bfe0d | 1940 | hash_for_each_possible(mm_slots_hash, mm_slot, hash, (unsigned long)mm) |
ba76149f AA |
1941 | if (mm == mm_slot->mm) |
1942 | return mm_slot; | |
43b5fbbd | 1943 | |
ba76149f AA |
1944 | return NULL; |
1945 | } | |
1946 | ||
1947 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
1948 | struct mm_slot *mm_slot) | |
1949 | { | |
ba76149f | 1950 | mm_slot->mm = mm; |
43b5fbbd | 1951 | hash_add(mm_slots_hash, &mm_slot->hash, (long)mm); |
ba76149f AA |
1952 | } |
1953 | ||
1954 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
1955 | { | |
1956 | return atomic_read(&mm->mm_users) == 0; | |
1957 | } | |
1958 | ||
1959 | int __khugepaged_enter(struct mm_struct *mm) | |
1960 | { | |
1961 | struct mm_slot *mm_slot; | |
1962 | int wakeup; | |
1963 | ||
1964 | mm_slot = alloc_mm_slot(); | |
1965 | if (!mm_slot) | |
1966 | return -ENOMEM; | |
1967 | ||
1968 | /* __khugepaged_exit() must not run from under us */ | |
1969 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
1970 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
1971 | free_mm_slot(mm_slot); | |
1972 | return 0; | |
1973 | } | |
1974 | ||
1975 | spin_lock(&khugepaged_mm_lock); | |
1976 | insert_to_mm_slots_hash(mm, mm_slot); | |
1977 | /* | |
1978 | * Insert just behind the scanning cursor, to let the area settle | |
1979 | * down a little. | |
1980 | */ | |
1981 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
1982 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
1983 | spin_unlock(&khugepaged_mm_lock); | |
1984 | ||
1985 | atomic_inc(&mm->mm_count); | |
1986 | if (wakeup) | |
1987 | wake_up_interruptible(&khugepaged_wait); | |
1988 | ||
1989 | return 0; | |
1990 | } | |
1991 | ||
1992 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
1993 | { | |
1994 | unsigned long hstart, hend; | |
1995 | if (!vma->anon_vma) | |
1996 | /* | |
1997 | * Not yet faulted in so we will register later in the | |
1998 | * page fault if needed. | |
1999 | */ | |
2000 | return 0; | |
78f11a25 | 2001 | if (vma->vm_ops) |
ba76149f AA |
2002 | /* khugepaged not yet working on file or special mappings */ |
2003 | return 0; | |
b3b9c293 | 2004 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
2005 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2006 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2007 | if (hstart < hend) | |
2008 | return khugepaged_enter(vma); | |
2009 | return 0; | |
2010 | } | |
2011 | ||
2012 | void __khugepaged_exit(struct mm_struct *mm) | |
2013 | { | |
2014 | struct mm_slot *mm_slot; | |
2015 | int free = 0; | |
2016 | ||
2017 | spin_lock(&khugepaged_mm_lock); | |
2018 | mm_slot = get_mm_slot(mm); | |
2019 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
43b5fbbd | 2020 | hash_del(&mm_slot->hash); |
ba76149f AA |
2021 | list_del(&mm_slot->mm_node); |
2022 | free = 1; | |
2023 | } | |
d788e80a | 2024 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
2025 | |
2026 | if (free) { | |
ba76149f AA |
2027 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
2028 | free_mm_slot(mm_slot); | |
2029 | mmdrop(mm); | |
2030 | } else if (mm_slot) { | |
ba76149f AA |
2031 | /* |
2032 | * This is required to serialize against | |
2033 | * khugepaged_test_exit() (which is guaranteed to run | |
2034 | * under mmap sem read mode). Stop here (after we | |
2035 | * return all pagetables will be destroyed) until | |
2036 | * khugepaged has finished working on the pagetables | |
2037 | * under the mmap_sem. | |
2038 | */ | |
2039 | down_write(&mm->mmap_sem); | |
2040 | up_write(&mm->mmap_sem); | |
d788e80a | 2041 | } |
ba76149f AA |
2042 | } |
2043 | ||
2044 | static void release_pte_page(struct page *page) | |
2045 | { | |
2046 | /* 0 stands for page_is_file_cache(page) == false */ | |
2047 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2048 | unlock_page(page); | |
2049 | putback_lru_page(page); | |
2050 | } | |
2051 | ||
2052 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
2053 | { | |
2054 | while (--_pte >= pte) { | |
2055 | pte_t pteval = *_pte; | |
2056 | if (!pte_none(pteval)) | |
2057 | release_pte_page(pte_page(pteval)); | |
2058 | } | |
2059 | } | |
2060 | ||
ba76149f AA |
2061 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, |
2062 | unsigned long address, | |
2063 | pte_t *pte) | |
2064 | { | |
2065 | struct page *page; | |
2066 | pte_t *_pte; | |
344aa35c | 2067 | int referenced = 0, none = 0; |
ba76149f AA |
2068 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; |
2069 | _pte++, address += PAGE_SIZE) { | |
2070 | pte_t pteval = *_pte; | |
2071 | if (pte_none(pteval)) { | |
2072 | if (++none <= khugepaged_max_ptes_none) | |
2073 | continue; | |
344aa35c | 2074 | else |
ba76149f | 2075 | goto out; |
ba76149f | 2076 | } |
344aa35c | 2077 | if (!pte_present(pteval) || !pte_write(pteval)) |
ba76149f | 2078 | goto out; |
ba76149f | 2079 | page = vm_normal_page(vma, address, pteval); |
344aa35c | 2080 | if (unlikely(!page)) |
ba76149f | 2081 | goto out; |
344aa35c | 2082 | |
ba76149f AA |
2083 | VM_BUG_ON(PageCompound(page)); |
2084 | BUG_ON(!PageAnon(page)); | |
2085 | VM_BUG_ON(!PageSwapBacked(page)); | |
2086 | ||
2087 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
344aa35c | 2088 | if (page_count(page) != 1) |
ba76149f | 2089 | goto out; |
ba76149f AA |
2090 | /* |
2091 | * We can do it before isolate_lru_page because the | |
2092 | * page can't be freed from under us. NOTE: PG_lock | |
2093 | * is needed to serialize against split_huge_page | |
2094 | * when invoked from the VM. | |
2095 | */ | |
344aa35c | 2096 | if (!trylock_page(page)) |
ba76149f | 2097 | goto out; |
ba76149f AA |
2098 | /* |
2099 | * Isolate the page to avoid collapsing an hugepage | |
2100 | * currently in use by the VM. | |
2101 | */ | |
2102 | if (isolate_lru_page(page)) { | |
2103 | unlock_page(page); | |
ba76149f AA |
2104 | goto out; |
2105 | } | |
2106 | /* 0 stands for page_is_file_cache(page) == false */ | |
2107 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
2108 | VM_BUG_ON(!PageLocked(page)); | |
2109 | VM_BUG_ON(PageLRU(page)); | |
2110 | ||
2111 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
2112 | if (pte_young(pteval) || PageReferenced(page) || |
2113 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2114 | referenced = 1; |
2115 | } | |
344aa35c BL |
2116 | if (likely(referenced)) |
2117 | return 1; | |
ba76149f | 2118 | out: |
344aa35c BL |
2119 | release_pte_pages(pte, _pte); |
2120 | return 0; | |
ba76149f AA |
2121 | } |
2122 | ||
2123 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
2124 | struct vm_area_struct *vma, | |
2125 | unsigned long address, | |
2126 | spinlock_t *ptl) | |
2127 | { | |
2128 | pte_t *_pte; | |
2129 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
2130 | pte_t pteval = *_pte; | |
2131 | struct page *src_page; | |
2132 | ||
2133 | if (pte_none(pteval)) { | |
2134 | clear_user_highpage(page, address); | |
2135 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
2136 | } else { | |
2137 | src_page = pte_page(pteval); | |
2138 | copy_user_highpage(page, src_page, address, vma); | |
2139 | VM_BUG_ON(page_mapcount(src_page) != 1); | |
ba76149f AA |
2140 | release_pte_page(src_page); |
2141 | /* | |
2142 | * ptl mostly unnecessary, but preempt has to | |
2143 | * be disabled to update the per-cpu stats | |
2144 | * inside page_remove_rmap(). | |
2145 | */ | |
2146 | spin_lock(ptl); | |
2147 | /* | |
2148 | * paravirt calls inside pte_clear here are | |
2149 | * superfluous. | |
2150 | */ | |
2151 | pte_clear(vma->vm_mm, address, _pte); | |
2152 | page_remove_rmap(src_page); | |
2153 | spin_unlock(ptl); | |
2154 | free_page_and_swap_cache(src_page); | |
2155 | } | |
2156 | ||
2157 | address += PAGE_SIZE; | |
2158 | page++; | |
2159 | } | |
2160 | } | |
2161 | ||
26234f36 | 2162 | static void khugepaged_alloc_sleep(void) |
ba76149f | 2163 | { |
26234f36 XG |
2164 | wait_event_freezable_timeout(khugepaged_wait, false, |
2165 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
2166 | } | |
ba76149f | 2167 | |
26234f36 XG |
2168 | #ifdef CONFIG_NUMA |
2169 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2170 | { | |
2171 | if (IS_ERR(*hpage)) { | |
2172 | if (!*wait) | |
2173 | return false; | |
2174 | ||
2175 | *wait = false; | |
e3b4126c | 2176 | *hpage = NULL; |
26234f36 XG |
2177 | khugepaged_alloc_sleep(); |
2178 | } else if (*hpage) { | |
2179 | put_page(*hpage); | |
2180 | *hpage = NULL; | |
2181 | } | |
2182 | ||
2183 | return true; | |
2184 | } | |
2185 | ||
2186 | static struct page | |
2187 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2188 | struct vm_area_struct *vma, unsigned long address, | |
2189 | int node) | |
2190 | { | |
0bbbc0b3 | 2191 | VM_BUG_ON(*hpage); |
ce83d217 AA |
2192 | /* |
2193 | * Allocate the page while the vma is still valid and under | |
2194 | * the mmap_sem read mode so there is no memory allocation | |
2195 | * later when we take the mmap_sem in write mode. This is more | |
2196 | * friendly behavior (OTOH it may actually hide bugs) to | |
2197 | * filesystems in userland with daemons allocating memory in | |
2198 | * the userland I/O paths. Allocating memory with the | |
2199 | * mmap_sem in read mode is good idea also to allow greater | |
2200 | * scalability. | |
2201 | */ | |
26234f36 | 2202 | *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, |
cc5d462f | 2203 | node, __GFP_OTHER_NODE); |
692e0b35 AA |
2204 | |
2205 | /* | |
2206 | * After allocating the hugepage, release the mmap_sem read lock in | |
2207 | * preparation for taking it in write mode. | |
2208 | */ | |
2209 | up_read(&mm->mmap_sem); | |
26234f36 | 2210 | if (unlikely(!*hpage)) { |
81ab4201 | 2211 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 2212 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 2213 | return NULL; |
ce83d217 | 2214 | } |
26234f36 | 2215 | |
65b3c07b | 2216 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
2217 | return *hpage; |
2218 | } | |
2219 | #else | |
2220 | static struct page *khugepaged_alloc_hugepage(bool *wait) | |
2221 | { | |
2222 | struct page *hpage; | |
2223 | ||
2224 | do { | |
2225 | hpage = alloc_hugepage(khugepaged_defrag()); | |
2226 | if (!hpage) { | |
2227 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
2228 | if (!*wait) | |
2229 | return NULL; | |
2230 | ||
2231 | *wait = false; | |
2232 | khugepaged_alloc_sleep(); | |
2233 | } else | |
2234 | count_vm_event(THP_COLLAPSE_ALLOC); | |
2235 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
2236 | ||
2237 | return hpage; | |
2238 | } | |
2239 | ||
2240 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2241 | { | |
2242 | if (!*hpage) | |
2243 | *hpage = khugepaged_alloc_hugepage(wait); | |
2244 | ||
2245 | if (unlikely(!*hpage)) | |
2246 | return false; | |
2247 | ||
2248 | return true; | |
2249 | } | |
2250 | ||
2251 | static struct page | |
2252 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2253 | struct vm_area_struct *vma, unsigned long address, | |
2254 | int node) | |
2255 | { | |
2256 | up_read(&mm->mmap_sem); | |
2257 | VM_BUG_ON(!*hpage); | |
2258 | return *hpage; | |
2259 | } | |
692e0b35 AA |
2260 | #endif |
2261 | ||
fa475e51 BL |
2262 | static bool hugepage_vma_check(struct vm_area_struct *vma) |
2263 | { | |
2264 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || | |
2265 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
2266 | return false; | |
2267 | ||
2268 | if (!vma->anon_vma || vma->vm_ops) | |
2269 | return false; | |
2270 | if (is_vma_temporary_stack(vma)) | |
2271 | return false; | |
2272 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); | |
2273 | return true; | |
2274 | } | |
2275 | ||
26234f36 XG |
2276 | static void collapse_huge_page(struct mm_struct *mm, |
2277 | unsigned long address, | |
2278 | struct page **hpage, | |
2279 | struct vm_area_struct *vma, | |
2280 | int node) | |
2281 | { | |
26234f36 XG |
2282 | pmd_t *pmd, _pmd; |
2283 | pte_t *pte; | |
2284 | pgtable_t pgtable; | |
2285 | struct page *new_page; | |
2286 | spinlock_t *ptl; | |
2287 | int isolated; | |
2288 | unsigned long hstart, hend; | |
2ec74c3e SG |
2289 | unsigned long mmun_start; /* For mmu_notifiers */ |
2290 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2291 | |
2292 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2293 | ||
2294 | /* release the mmap_sem read lock. */ | |
2295 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2296 | if (!new_page) | |
2297 | return; | |
2298 | ||
420256ef | 2299 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2300 | return; |
ba76149f AA |
2301 | |
2302 | /* | |
2303 | * Prevent all access to pagetables with the exception of | |
2304 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2305 | * handled by the anon_vma lock + PG_lock. | |
2306 | */ | |
2307 | down_write(&mm->mmap_sem); | |
2308 | if (unlikely(khugepaged_test_exit(mm))) | |
2309 | goto out; | |
2310 | ||
2311 | vma = find_vma(mm, address); | |
a8f531eb L |
2312 | if (!vma) |
2313 | goto out; | |
ba76149f AA |
2314 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2315 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2316 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2317 | goto out; | |
fa475e51 | 2318 | if (!hugepage_vma_check(vma)) |
a7d6e4ec | 2319 | goto out; |
6219049a BL |
2320 | pmd = mm_find_pmd(mm, address); |
2321 | if (!pmd) | |
ba76149f | 2322 | goto out; |
6219049a | 2323 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2324 | goto out; |
2325 | ||
4fc3f1d6 | 2326 | anon_vma_lock_write(vma->anon_vma); |
ba76149f AA |
2327 | |
2328 | pte = pte_offset_map(pmd, address); | |
2329 | ptl = pte_lockptr(mm, pmd); | |
2330 | ||
2ec74c3e SG |
2331 | mmun_start = address; |
2332 | mmun_end = address + HPAGE_PMD_SIZE; | |
2333 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
ba76149f AA |
2334 | spin_lock(&mm->page_table_lock); /* probably unnecessary */ |
2335 | /* | |
2336 | * After this gup_fast can't run anymore. This also removes | |
2337 | * any huge TLB entry from the CPU so we won't allow | |
2338 | * huge and small TLB entries for the same virtual address | |
2339 | * to avoid the risk of CPU bugs in that area. | |
2340 | */ | |
2ec74c3e | 2341 | _pmd = pmdp_clear_flush(vma, address, pmd); |
ba76149f | 2342 | spin_unlock(&mm->page_table_lock); |
2ec74c3e | 2343 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f AA |
2344 | |
2345 | spin_lock(ptl); | |
2346 | isolated = __collapse_huge_page_isolate(vma, address, pte); | |
2347 | spin_unlock(ptl); | |
ba76149f AA |
2348 | |
2349 | if (unlikely(!isolated)) { | |
453c7192 | 2350 | pte_unmap(pte); |
ba76149f AA |
2351 | spin_lock(&mm->page_table_lock); |
2352 | BUG_ON(!pmd_none(*pmd)); | |
7c342512 AK |
2353 | /* |
2354 | * We can only use set_pmd_at when establishing | |
2355 | * hugepmds and never for establishing regular pmds that | |
2356 | * points to regular pagetables. Use pmd_populate for that | |
2357 | */ | |
2358 | pmd_populate(mm, pmd, pmd_pgtable(_pmd)); | |
ba76149f | 2359 | spin_unlock(&mm->page_table_lock); |
08b52706 | 2360 | anon_vma_unlock_write(vma->anon_vma); |
ce83d217 | 2361 | goto out; |
ba76149f AA |
2362 | } |
2363 | ||
2364 | /* | |
2365 | * All pages are isolated and locked so anon_vma rmap | |
2366 | * can't run anymore. | |
2367 | */ | |
08b52706 | 2368 | anon_vma_unlock_write(vma->anon_vma); |
ba76149f AA |
2369 | |
2370 | __collapse_huge_page_copy(pte, new_page, vma, address, ptl); | |
453c7192 | 2371 | pte_unmap(pte); |
ba76149f AA |
2372 | __SetPageUptodate(new_page); |
2373 | pgtable = pmd_pgtable(_pmd); | |
ba76149f | 2374 | |
3122359a KS |
2375 | _pmd = mk_huge_pmd(new_page, vma->vm_page_prot); |
2376 | _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); | |
ba76149f AA |
2377 | |
2378 | /* | |
2379 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2380 | * this is needed to avoid the copy_huge_page writes to become | |
2381 | * visible after the set_pmd_at() write. | |
2382 | */ | |
2383 | smp_wmb(); | |
2384 | ||
2385 | spin_lock(&mm->page_table_lock); | |
2386 | BUG_ON(!pmd_none(*pmd)); | |
2387 | page_add_new_anon_rmap(new_page, vma, address); | |
fce144b4 | 2388 | pgtable_trans_huge_deposit(mm, pmd, pgtable); |
ba76149f | 2389 | set_pmd_at(mm, address, pmd, _pmd); |
b113da65 | 2390 | update_mmu_cache_pmd(vma, address, pmd); |
ba76149f AA |
2391 | spin_unlock(&mm->page_table_lock); |
2392 | ||
2393 | *hpage = NULL; | |
420256ef | 2394 | |
ba76149f | 2395 | khugepaged_pages_collapsed++; |
ce83d217 | 2396 | out_up_write: |
ba76149f | 2397 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2398 | return; |
2399 | ||
ce83d217 | 2400 | out: |
678ff896 | 2401 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2402 | goto out_up_write; |
ba76149f AA |
2403 | } |
2404 | ||
2405 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2406 | struct vm_area_struct *vma, | |
2407 | unsigned long address, | |
2408 | struct page **hpage) | |
2409 | { | |
ba76149f AA |
2410 | pmd_t *pmd; |
2411 | pte_t *pte, *_pte; | |
2412 | int ret = 0, referenced = 0, none = 0; | |
2413 | struct page *page; | |
2414 | unsigned long _address; | |
2415 | spinlock_t *ptl; | |
00ef2d2f | 2416 | int node = NUMA_NO_NODE; |
ba76149f AA |
2417 | |
2418 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2419 | ||
6219049a BL |
2420 | pmd = mm_find_pmd(mm, address); |
2421 | if (!pmd) | |
ba76149f | 2422 | goto out; |
6219049a | 2423 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2424 | goto out; |
2425 | ||
2426 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2427 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2428 | _pte++, _address += PAGE_SIZE) { | |
2429 | pte_t pteval = *_pte; | |
2430 | if (pte_none(pteval)) { | |
2431 | if (++none <= khugepaged_max_ptes_none) | |
2432 | continue; | |
2433 | else | |
2434 | goto out_unmap; | |
2435 | } | |
2436 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2437 | goto out_unmap; | |
2438 | page = vm_normal_page(vma, _address, pteval); | |
2439 | if (unlikely(!page)) | |
2440 | goto out_unmap; | |
5c4b4be3 AK |
2441 | /* |
2442 | * Chose the node of the first page. This could | |
2443 | * be more sophisticated and look at more pages, | |
2444 | * but isn't for now. | |
2445 | */ | |
00ef2d2f | 2446 | if (node == NUMA_NO_NODE) |
5c4b4be3 | 2447 | node = page_to_nid(page); |
ba76149f AA |
2448 | VM_BUG_ON(PageCompound(page)); |
2449 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) | |
2450 | goto out_unmap; | |
2451 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2452 | if (page_count(page) != 1) | |
2453 | goto out_unmap; | |
8ee53820 AA |
2454 | if (pte_young(pteval) || PageReferenced(page) || |
2455 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2456 | referenced = 1; |
2457 | } | |
2458 | if (referenced) | |
2459 | ret = 1; | |
2460 | out_unmap: | |
2461 | pte_unmap_unlock(pte, ptl); | |
ce83d217 AA |
2462 | if (ret) |
2463 | /* collapse_huge_page will return with the mmap_sem released */ | |
5c4b4be3 | 2464 | collapse_huge_page(mm, address, hpage, vma, node); |
ba76149f AA |
2465 | out: |
2466 | return ret; | |
2467 | } | |
2468 | ||
2469 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2470 | { | |
2471 | struct mm_struct *mm = mm_slot->mm; | |
2472 | ||
b9980cdc | 2473 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2474 | |
2475 | if (khugepaged_test_exit(mm)) { | |
2476 | /* free mm_slot */ | |
43b5fbbd | 2477 | hash_del(&mm_slot->hash); |
ba76149f AA |
2478 | list_del(&mm_slot->mm_node); |
2479 | ||
2480 | /* | |
2481 | * Not strictly needed because the mm exited already. | |
2482 | * | |
2483 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2484 | */ | |
2485 | ||
2486 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2487 | free_mm_slot(mm_slot); | |
2488 | mmdrop(mm); | |
2489 | } | |
2490 | } | |
2491 | ||
2492 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2493 | struct page **hpage) | |
2f1da642 HS |
2494 | __releases(&khugepaged_mm_lock) |
2495 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2496 | { |
2497 | struct mm_slot *mm_slot; | |
2498 | struct mm_struct *mm; | |
2499 | struct vm_area_struct *vma; | |
2500 | int progress = 0; | |
2501 | ||
2502 | VM_BUG_ON(!pages); | |
b9980cdc | 2503 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2504 | |
2505 | if (khugepaged_scan.mm_slot) | |
2506 | mm_slot = khugepaged_scan.mm_slot; | |
2507 | else { | |
2508 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2509 | struct mm_slot, mm_node); | |
2510 | khugepaged_scan.address = 0; | |
2511 | khugepaged_scan.mm_slot = mm_slot; | |
2512 | } | |
2513 | spin_unlock(&khugepaged_mm_lock); | |
2514 | ||
2515 | mm = mm_slot->mm; | |
2516 | down_read(&mm->mmap_sem); | |
2517 | if (unlikely(khugepaged_test_exit(mm))) | |
2518 | vma = NULL; | |
2519 | else | |
2520 | vma = find_vma(mm, khugepaged_scan.address); | |
2521 | ||
2522 | progress++; | |
2523 | for (; vma; vma = vma->vm_next) { | |
2524 | unsigned long hstart, hend; | |
2525 | ||
2526 | cond_resched(); | |
2527 | if (unlikely(khugepaged_test_exit(mm))) { | |
2528 | progress++; | |
2529 | break; | |
2530 | } | |
fa475e51 BL |
2531 | if (!hugepage_vma_check(vma)) { |
2532 | skip: | |
ba76149f AA |
2533 | progress++; |
2534 | continue; | |
2535 | } | |
ba76149f AA |
2536 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2537 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2538 | if (hstart >= hend) |
2539 | goto skip; | |
2540 | if (khugepaged_scan.address > hend) | |
2541 | goto skip; | |
ba76149f AA |
2542 | if (khugepaged_scan.address < hstart) |
2543 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2544 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2545 | |
2546 | while (khugepaged_scan.address < hend) { | |
2547 | int ret; | |
2548 | cond_resched(); | |
2549 | if (unlikely(khugepaged_test_exit(mm))) | |
2550 | goto breakouterloop; | |
2551 | ||
2552 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2553 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2554 | hend); | |
2555 | ret = khugepaged_scan_pmd(mm, vma, | |
2556 | khugepaged_scan.address, | |
2557 | hpage); | |
2558 | /* move to next address */ | |
2559 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2560 | progress += HPAGE_PMD_NR; | |
2561 | if (ret) | |
2562 | /* we released mmap_sem so break loop */ | |
2563 | goto breakouterloop_mmap_sem; | |
2564 | if (progress >= pages) | |
2565 | goto breakouterloop; | |
2566 | } | |
2567 | } | |
2568 | breakouterloop: | |
2569 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2570 | breakouterloop_mmap_sem: | |
2571 | ||
2572 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2573 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2574 | /* |
2575 | * Release the current mm_slot if this mm is about to die, or | |
2576 | * if we scanned all vmas of this mm. | |
2577 | */ | |
2578 | if (khugepaged_test_exit(mm) || !vma) { | |
2579 | /* | |
2580 | * Make sure that if mm_users is reaching zero while | |
2581 | * khugepaged runs here, khugepaged_exit will find | |
2582 | * mm_slot not pointing to the exiting mm. | |
2583 | */ | |
2584 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2585 | khugepaged_scan.mm_slot = list_entry( | |
2586 | mm_slot->mm_node.next, | |
2587 | struct mm_slot, mm_node); | |
2588 | khugepaged_scan.address = 0; | |
2589 | } else { | |
2590 | khugepaged_scan.mm_slot = NULL; | |
2591 | khugepaged_full_scans++; | |
2592 | } | |
2593 | ||
2594 | collect_mm_slot(mm_slot); | |
2595 | } | |
2596 | ||
2597 | return progress; | |
2598 | } | |
2599 | ||
2600 | static int khugepaged_has_work(void) | |
2601 | { | |
2602 | return !list_empty(&khugepaged_scan.mm_head) && | |
2603 | khugepaged_enabled(); | |
2604 | } | |
2605 | ||
2606 | static int khugepaged_wait_event(void) | |
2607 | { | |
2608 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2609 | kthread_should_stop(); |
ba76149f AA |
2610 | } |
2611 | ||
d516904b | 2612 | static void khugepaged_do_scan(void) |
ba76149f | 2613 | { |
d516904b | 2614 | struct page *hpage = NULL; |
ba76149f AA |
2615 | unsigned int progress = 0, pass_through_head = 0; |
2616 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2617 | bool wait = true; |
ba76149f AA |
2618 | |
2619 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2620 | ||
2621 | while (progress < pages) { | |
26234f36 | 2622 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2623 | break; |
26234f36 | 2624 | |
420256ef | 2625 | cond_resched(); |
ba76149f | 2626 | |
878aee7d AA |
2627 | if (unlikely(kthread_should_stop() || freezing(current))) |
2628 | break; | |
2629 | ||
ba76149f AA |
2630 | spin_lock(&khugepaged_mm_lock); |
2631 | if (!khugepaged_scan.mm_slot) | |
2632 | pass_through_head++; | |
2633 | if (khugepaged_has_work() && | |
2634 | pass_through_head < 2) | |
2635 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2636 | &hpage); |
ba76149f AA |
2637 | else |
2638 | progress = pages; | |
2639 | spin_unlock(&khugepaged_mm_lock); | |
2640 | } | |
ba76149f | 2641 | |
d516904b XG |
2642 | if (!IS_ERR_OR_NULL(hpage)) |
2643 | put_page(hpage); | |
0bbbc0b3 AA |
2644 | } |
2645 | ||
2017c0bf XG |
2646 | static void khugepaged_wait_work(void) |
2647 | { | |
2648 | try_to_freeze(); | |
2649 | ||
2650 | if (khugepaged_has_work()) { | |
2651 | if (!khugepaged_scan_sleep_millisecs) | |
2652 | return; | |
2653 | ||
2654 | wait_event_freezable_timeout(khugepaged_wait, | |
2655 | kthread_should_stop(), | |
2656 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2657 | return; | |
2658 | } | |
2659 | ||
2660 | if (khugepaged_enabled()) | |
2661 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2662 | } | |
2663 | ||
ba76149f AA |
2664 | static int khugepaged(void *none) |
2665 | { | |
2666 | struct mm_slot *mm_slot; | |
2667 | ||
878aee7d | 2668 | set_freezable(); |
ba76149f AA |
2669 | set_user_nice(current, 19); |
2670 | ||
b7231789 XG |
2671 | while (!kthread_should_stop()) { |
2672 | khugepaged_do_scan(); | |
2673 | khugepaged_wait_work(); | |
2674 | } | |
ba76149f AA |
2675 | |
2676 | spin_lock(&khugepaged_mm_lock); | |
2677 | mm_slot = khugepaged_scan.mm_slot; | |
2678 | khugepaged_scan.mm_slot = NULL; | |
2679 | if (mm_slot) | |
2680 | collect_mm_slot(mm_slot); | |
2681 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2682 | return 0; |
2683 | } | |
2684 | ||
c5a647d0 KS |
2685 | static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, |
2686 | unsigned long haddr, pmd_t *pmd) | |
2687 | { | |
2688 | struct mm_struct *mm = vma->vm_mm; | |
2689 | pgtable_t pgtable; | |
2690 | pmd_t _pmd; | |
2691 | int i; | |
2692 | ||
2693 | pmdp_clear_flush(vma, haddr, pmd); | |
2694 | /* leave pmd empty until pte is filled */ | |
2695 | ||
6b0b50b0 | 2696 | pgtable = pgtable_trans_huge_withdraw(mm, pmd); |
c5a647d0 KS |
2697 | pmd_populate(mm, &_pmd, pgtable); |
2698 | ||
2699 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
2700 | pte_t *pte, entry; | |
2701 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
2702 | entry = pte_mkspecial(entry); | |
2703 | pte = pte_offset_map(&_pmd, haddr); | |
2704 | VM_BUG_ON(!pte_none(*pte)); | |
2705 | set_pte_at(mm, haddr, pte, entry); | |
2706 | pte_unmap(pte); | |
2707 | } | |
2708 | smp_wmb(); /* make pte visible before pmd */ | |
2709 | pmd_populate(mm, pmd, pgtable); | |
97ae1749 | 2710 | put_huge_zero_page(); |
c5a647d0 KS |
2711 | } |
2712 | ||
e180377f KS |
2713 | void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, |
2714 | pmd_t *pmd) | |
71e3aac0 AA |
2715 | { |
2716 | struct page *page; | |
e180377f | 2717 | struct mm_struct *mm = vma->vm_mm; |
c5a647d0 KS |
2718 | unsigned long haddr = address & HPAGE_PMD_MASK; |
2719 | unsigned long mmun_start; /* For mmu_notifiers */ | |
2720 | unsigned long mmun_end; /* For mmu_notifiers */ | |
e180377f KS |
2721 | |
2722 | BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); | |
71e3aac0 | 2723 | |
c5a647d0 KS |
2724 | mmun_start = haddr; |
2725 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
750e8165 | 2726 | again: |
c5a647d0 | 2727 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2728 | spin_lock(&mm->page_table_lock); |
2729 | if (unlikely(!pmd_trans_huge(*pmd))) { | |
2730 | spin_unlock(&mm->page_table_lock); | |
c5a647d0 KS |
2731 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2732 | return; | |
2733 | } | |
2734 | if (is_huge_zero_pmd(*pmd)) { | |
2735 | __split_huge_zero_page_pmd(vma, haddr, pmd); | |
2736 | spin_unlock(&mm->page_table_lock); | |
2737 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
2738 | return; |
2739 | } | |
2740 | page = pmd_page(*pmd); | |
2741 | VM_BUG_ON(!page_count(page)); | |
2742 | get_page(page); | |
2743 | spin_unlock(&mm->page_table_lock); | |
c5a647d0 | 2744 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
2745 | |
2746 | split_huge_page(page); | |
2747 | ||
2748 | put_page(page); | |
750e8165 HD |
2749 | |
2750 | /* | |
2751 | * We don't always have down_write of mmap_sem here: a racing | |
2752 | * do_huge_pmd_wp_page() might have copied-on-write to another | |
2753 | * huge page before our split_huge_page() got the anon_vma lock. | |
2754 | */ | |
2755 | if (unlikely(pmd_trans_huge(*pmd))) | |
2756 | goto again; | |
71e3aac0 | 2757 | } |
94fcc585 | 2758 | |
e180377f KS |
2759 | void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, |
2760 | pmd_t *pmd) | |
2761 | { | |
2762 | struct vm_area_struct *vma; | |
2763 | ||
2764 | vma = find_vma(mm, address); | |
2765 | BUG_ON(vma == NULL); | |
2766 | split_huge_page_pmd(vma, address, pmd); | |
2767 | } | |
2768 | ||
94fcc585 AA |
2769 | static void split_huge_page_address(struct mm_struct *mm, |
2770 | unsigned long address) | |
2771 | { | |
94fcc585 AA |
2772 | pmd_t *pmd; |
2773 | ||
2774 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2775 | ||
6219049a BL |
2776 | pmd = mm_find_pmd(mm, address); |
2777 | if (!pmd) | |
94fcc585 AA |
2778 | return; |
2779 | /* | |
2780 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2781 | * materialize from under us. | |
2782 | */ | |
e180377f | 2783 | split_huge_page_pmd_mm(mm, address, pmd); |
94fcc585 AA |
2784 | } |
2785 | ||
2786 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2787 | unsigned long start, | |
2788 | unsigned long end, | |
2789 | long adjust_next) | |
2790 | { | |
2791 | /* | |
2792 | * If the new start address isn't hpage aligned and it could | |
2793 | * previously contain an hugepage: check if we need to split | |
2794 | * an huge pmd. | |
2795 | */ | |
2796 | if (start & ~HPAGE_PMD_MASK && | |
2797 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2798 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2799 | split_huge_page_address(vma->vm_mm, start); | |
2800 | ||
2801 | /* | |
2802 | * If the new end address isn't hpage aligned and it could | |
2803 | * previously contain an hugepage: check if we need to split | |
2804 | * an huge pmd. | |
2805 | */ | |
2806 | if (end & ~HPAGE_PMD_MASK && | |
2807 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2808 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2809 | split_huge_page_address(vma->vm_mm, end); | |
2810 | ||
2811 | /* | |
2812 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2813 | * vm_next->vm_start isn't page aligned and it could previously | |
2814 | * contain an hugepage: check if we need to split an huge pmd. | |
2815 | */ | |
2816 | if (adjust_next > 0) { | |
2817 | struct vm_area_struct *next = vma->vm_next; | |
2818 | unsigned long nstart = next->vm_start; | |
2819 | nstart += adjust_next << PAGE_SHIFT; | |
2820 | if (nstart & ~HPAGE_PMD_MASK && | |
2821 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2822 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2823 | split_huge_page_address(next->vm_mm, nstart); | |
2824 | } | |
2825 | } |